Non-uniform transmission of synchronization signals

ABSTRACT

The base station that is configured to transmit in a beamformed manner may set different transmission rates for different directions of the beams. During an initial access stage, the base station may set different transmission rates for different transmission directions, and may transmit initial access signals based on the transmission rates in the different transmission directions The apparatus may be a base station. The base station determines transmission rates for a plurality of transmission directions, where each transmission rate is determined for a respective transmission direction of the plurality of transmission directions. The base station transmits at least one initial access signal in each of one or more of the plurality of transmission directions based on a corresponding transmission rate of the transmission rates.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application Ser.No. 62/377,500, entitled “NON-UNIFORM TRANSMISSION OF SYNCHRONIZATIONSIGNALS” and filed on Aug. 19, 2016, and U.S. Provisional ApplicationSer. No. 62/456,623, entitled “NON-UNIFORM TRANSMISSION OFSYNCHRONIZATION SIGNALS” and filed on Feb. 8, 2017, which are expresslyincorporated by reference herein in their entirety.

BACKGROUND Field

The present disclosure relates generally to communication systems, andmore particularly, to wireless communication via beamforming.

Background

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources. Examples of suchmultiple-access technologies include code division multiple access(CDMA) systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, orthogonal frequency divisionmultiple access (OFDMA) systems, single-carrier frequency divisionmultiple access (SC-FDMA) systems, and time division synchronous codedivision multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example telecommunication standardis Long Term Evolution (LTE). LTE is a set of enhancements to theUniversal Mobile Telecommunications System (UMTS) mobile standardpromulgated by Third Generation Partnership Project (3GPP). LTE isdesigned to support mobile broadband access through improved spectralefficiency, lowered costs, and improved services using OFDMA on thedownlink, SC-FDMA on the uplink, and multiple-input multiple-output(MIMO) antenna technology. However, as the demand for mobile broadbandaccess continues to increase, there exists a need for furtherimprovements in LTE technology. These improvements may also beapplicable to other multi-access technologies and the telecommunicationstandards that employ these technologies.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

A base station (e.g., a millimeter wave base station) may transmit andreceive signals in a beamformed manner (e.g., in a directional manner),sweeping through the angular regions in various directions. The basestation may set different transmission rates for different directions ofthe beams. Thus, during an initial access stage, the base station mayset different transmission rates for different transmission directions,and may transmit initial access signals based on the transmission ratesin the different transmission directions.

In an aspect of the disclosure, a method, a computer-readable medium,and an apparatus are provided. The apparatus may be a base station. Thebase station determines a plurality of transmission rates, eachtransmission rate for a respective transmission direction of a pluralityof transmission directions. The base station transmits at least oneinitial access signal in one or more transmission directions of theplurality of transmission directions based on the transmission rate ofeach transmission direction of the one or more transmission directions.

In an, the apparatus may be a base station. The base station includesmeans for determining a plurality of transmission rates, eachtransmission rate for a respective transmission direction of a pluralityof transmission directions, and means for transmitting at least oneinitial access signal in one or more transmission directions of theplurality of transmission directions based on the transmission rate ofeach transmission direction of the one or more transmission directions.

In an aspect, the apparatus may be a base station including a memory andat least one processor coupled to the memory. The at least one processoris configured to: determine a plurality of transmission rates, eachtransmission rate for a respective transmission direction of a pluralityof transmission directions, and transmit at least one initial accesssignal in one or more transmission directions of the plurality oftransmission directions based on the transmission rate of eachtransmission direction of the one or more transmission directions.

In an aspect, a computer-readable medium storing computer executablecode for a base station includes code to: determine a plurality oftransmission rates, each transmission rate for a respective transmissiondirection of a plurality of transmission directions, and transmit atleast one initial access signal in one or more transmission directionsof the plurality of transmission directions based on the transmissionrate of each transmission direction of the one or more transmissiondirections.

In another aspect of the disclosure, a method, a computer-readablemedium, and an apparatus are provided. The apparatus may be a UE. The UEreceives, from a base station, one or more transmission rates of thebase station for a plurality of transmission directions, where eachtransmission rate is determined for a respective transmission directionof the plurality of transmission directions. The UE determines a firsttransmission rate of the base station corresponding to a firsttransmission direction of the plurality of transmission directions,where the UE is located in the first transmission direction. The UEconfigures at least one communication setting for communicating with thebase station based on the first transmission rate of the base station.

In an aspect, the apparatus may be a UE. The UE includes means forreceiving, from a base station, one or more transmission rates of thebase station for a plurality of transmission directions, where eachtransmission rate is determined for a respective transmission directionof the plurality of transmission directions. The UE includes means fordetermining a first transmission rate of the base station correspondingto a first transmission direction of the plurality of transmissiondirections, where the UE is located in the first transmission direction.The UE includes means for configuring at least one communication settingfor communicating with the base station based on the first transmissionrate of the base station.

In an aspect, the apparatus may be a UE including a memory and at leastone processor coupled to the memory. The at least one processor isconfigured to: receive, from a base station, one or more transmissionrates of the base station for a plurality of transmission directions,where each transmission rate is determined for a respective transmissiondirection of the plurality of transmission directions, determine a firsttransmission rate of the base station corresponding to a firsttransmission direction of the plurality of transmission directions,where the UE is located in the first transmission direction, andconfigure at least one communication setting for communicating with thebase station based on the first transmission rate of the base station.

In an aspect, a computer-readable medium storing computer executablecode for a UE includes code to: receive, from a base station, one ormore transmission rates of the base station for a plurality oftransmission directions, where each transmission rate is determined fora respective transmission direction of the plurality of transmissiondirections, determine a first transmission rate of the base stationcorresponding to a first transmission direction of the plurality oftransmission directions, where the UE is located in the firsttransmission direction, and configure at least one communication settingfor communicating with the base station based on the first transmissionrate of the base station.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network.

FIGS. 2A, 2B, 2C, and 2D are diagrams illustrating LTE examples of a DLframe structure, DL channels within the DL frame structure, an UL framestructure, and UL channels within the UL frame structure, respectively.

FIG. 3 is a diagram illustrating an example of an evolved Node B (eNB)and user equipment (UE) in an access network.

FIG. 4A is an example diagram illustrating transmission of beams in onesymbol.

FIG. 4B is an example diagram illustrating transmission of beams inanother symbol.

FIG. 5 is an example diagram illustrating a subframe structure forsynchronization in a millimeter wave communication system.

FIG. 6 is an example diagram illustrating transmission of initial accesssignals.

FIGS. 7A and 7B are example diagrams illustrating a first scenario witha uniform transmission rate across various transmission directions.

FIGS. 8A and 8B are example diagrams illustrating a second scenario withdifferent transmission rates for different groups of transmissiondirections

FIG. 9 is a diagram illustrating an example process according to anaspect of the disclosure.

FIG. 10 is an example diagram illustrating an approach to estimate anumber of UEs in unit angular ranges.

FIG. 11 is an example diagram illustrating a non-uniform sub-regionssurrounding a base station.

FIG. 12 is an example diagram illustrating a non-uniform sub-regionssurrounding a base station

FIG. 13 is a diagram illustrating an example process according to anaspect of the disclosure

FIG. 14 is a flowchart of a method of wireless communication, accordingto an aspect of the disclosure.

FIG. 15 is a flowchart of a method of wireless communication, accordingto an aspect of the disclosure.

FIG. 16 is a conceptual data flow diagram illustrating the data flowbetween different means/components in an exemplary apparatus.

FIG. 17 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system.

FIG. 18 is a flowchart of a method of wireless communication.

FIG. 19 is a conceptual data flow diagram illustrating the data flowbetween different means/components in an exemplary apparatus.

FIG. 20 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, components, circuits,processes, algorithms, etc. (collectively referred to as “elements”).These elements may be implemented using electronic hardware, computersoftware, or any combination thereof. Whether such elements areimplemented as hardware or software depends upon the particularapplication and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented as a “processing system” thatincludes one or more processors. Examples of processors includemicroprocessors, microcontrollers, graphics processing units (GPUs),central processing units (CPUs), application processors, digital signalprocessors (DSPs), reduced instruction set computing (RISC) processors,systems on a chip (SoC), baseband processors, field programmable gatearrays (FPGAs), programmable logic devices (PLDs), state machines, gatedlogic, discrete hardware circuits, and other suitable hardwareconfigured to perform the various functionality described throughoutthis disclosure. One or more processors in the processing system mayexecute software. Software shall be construed broadly to meaninstructions, instruction sets, code, code segments, program code,programs, subprograms, software components, applications, softwareapplications, software packages, routines, subroutines, objects,executables, threads of execution, procedures, functions, etc., whetherreferred to as software, firmware, middleware, microcode, hardwaredescription language, or otherwise.

Accordingly, in one or more example embodiments, the functions describedmay be implemented in hardware, software, or any combination thereof. Ifimplemented in software, the functions may be stored on or encoded asone or more instructions or code on a computer-readable medium.Computer-readable media includes computer storage media. Storage mediamay be any available media that can be accessed by a computer. By way ofexample, and not limitation, such computer-readable media can comprise arandom-access memory (RAM), a read-only memory (ROM), an electricallyerasable programmable ROM (EEPROM), optical disk storage, magnetic diskstorage, other magnetic storage devices, combinations of theaforementioned types of computer-readable media, or any other mediumthat can be used to store computer executable code in the form ofinstructions or data structures that can be accessed by a computer.

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network 100. The wireless communications system(also referred to as a wireless wide area network (WWAN)) includes basestations 102, UEs 104, and an Evolved Packet Core (EPC) 160. The basestations 102 may include macro cells (high power cellular base station)and/or small cells (low power cellular base station). The macro cellsinclude eNBs. The small cells include femtocells, picocells, andmicrocells.

The base stations 102 (collectively referred to as Evolved UniversalMobile Telecommunications System (UMTS) Terrestrial Radio Access Network(E-UTRAN)) interface with the EPC 160 through backhaul links 132 (e.g.,S1 interface). In addition to other functions, the base stations 102 mayperform one or more of the following functions: transfer of user data,radio channel ciphering and deciphering, integrity protection, headercompression, mobility control functions (e.g., handover, dualconnectivity), inter-cell interference coordination, connection setupand release, load balancing, distribution for non-access stratum (NAS)messages, NAS node selection, synchronization, radio access network(RAN) sharing, multimedia broadcast multicast service (MBMS), subscriberand equipment trace, RAN information management (RIM), paging,positioning, and delivery of warning messages. The base stations 102 maycommunicate directly or indirectly (e.g., through the EPC 160) with eachother over backhaul links 134 (e.g., X2 interface). The backhaul links134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Eachof the base stations 102 may provide communication coverage for arespective geographic coverage area 110. There may be overlappinggeographic coverage areas 110. For example, the small cell 102′ may havea coverage area 110′ that overlaps the coverage area 110 of one or moremacro base stations 102. A network that includes both small cell andmacro cells may be known as a heterogeneous network. A heterogeneousnetwork may also include Home Evolved Node Bs (eNBs) (HeNBs), which mayprovide service to a restricted group known as a closed subscriber group(CSG). The communication links 120 between the base stations 102 and theUEs 104 may include uplink (UL) (also referred to as reverse link)transmissions from a UE 104 to a base station 102 and/or downlink (DL)(also referred to as forward link) transmissions from a base station 102to a UE 104. The communication links 120 may use MIMO antennatechnology, including spatial multiplexing, beamforming, and/or transmitdiversity. The communication links may be through one or more carriers.The base stations 102/UEs 104 may use spectrum up to Y MHz (e.g., 5, 10,15, 20 MHz) bandwidth per carrier allocated in a carrier aggregation ofup to a total of Yx MHz (x component carriers) used for transmission ineach direction. The carriers may or may not be adjacent to each other.Allocation of carriers may be asymmetric with respect to DL and UL(e.g., more or less carriers may be allocated for DL than for UL). Thecomponent carriers may include a primary component carrier and one ormore secondary component carriers. A primary component carrier may bereferred to as a primary cell (PCell) and a secondary component carriermay be referred to as a secondary cell (SCell).

The wireless communications system may further include a Wi-Fi accesspoint (AP) 150 in communication with Wi-Fi stations (STAs) 152 viacommunication links 154 in a 5 GHz unlicensed frequency spectrum. Whencommunicating in an unlicensed frequency spectrum, the STAs 152/AP 150may perform a clear channel assessment (CCA) prior to communicating inorder to determine whether the channel is available.

The small cell 102′ may operate in a licensed and/or an unlicensedfrequency spectrum. When operating in an unlicensed frequency spectrum,the small cell 102′ may employ LTE and use the same 5 GHz unlicensedfrequency spectrum as used by the Wi-Fi AP 150. The small cell 102′,employing LTE in an unlicensed frequency spectrum, may boost coverage toand/or increase capacity of the access network. LTE in an unlicensedspectrum may be referred to as LTE-unlicensed (LTE-U), licensed assistedaccess (LAA), or MuLTEfire.

The millimeter wave (mmW) base station 180 may operate in mmWfrequencies and/or near mmW frequencies in communication with the UE182. Extremely high frequency (EHF) is part of the RF in theelectromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and awavelength between 1 millimeter and 10 millimeters. Radio waves in theband may be referred to as a millimeter wave. Near mmW may extend downto a frequency of 3 GHz with a wavelength of 100 millimeters. The superhigh frequency (SHF) band extends between 3 GHz and 30 GHz, alsoreferred to as centimeter wave. Communications using the mmW/near mmWradio frequency band has extremely high path loss and a short range. ThemmW base station 180 may utilize beamforming 184 with the UE 182 tocompensate for the extremely high path loss and short range.

The EPC 160 may include a Mobility Management Entity (MME) 162, otherMMEs 164, a Serving Gateway 166, a Multimedia Broadcast MulticastService (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC)170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be incommunication with a Home Subscriber Server (HSS) 174. The MME 162 isthe control node that processes the signaling between the UEs 104 andthe EPC 160. Generally, the MME 162 provides bearer and connectionmanagement. All user Internet protocol (IP) packets are transferredthrough the Serving Gateway 166, which itself is connected to the PDNGateway 172. The PDN Gateway 172 provides UE IP address allocation aswell as other functions. The PDN Gateway 172 and the BM-SC 170 areconnected to the IP Services 176. The IP Services 176 may include theInternet, an intranet, an IP Multimedia Subsystem (IMS), a PS StreamingService (PSS), and/or other IP services. The BM-SC 170 may providefunctions for MBMS user service provisioning and delivery. The BM-SC 170may serve as an entry point for content provider MBMS transmission, maybe used to authorize and initiate MBMS Bearer Services within a publicland mobile network (PLMN), and may be used to schedule MBMStransmissions. The MBMS Gateway 168 may be used to distribute MBMStraffic to the base stations 102 belonging to a Multicast BroadcastSingle Frequency Network (MBSFN) area broadcasting a particular service,and may be responsible for session management (start/stop) and forcollecting eMBMS related charging information.

The base station may also be referred to as a Node B, evolved Node B(eNB), an access point, a base transceiver station, a radio basestation, a radio transceiver, a transceiver function, a basic serviceset (BSS), an extended service set (ESS), or some other suitableterminology. The base station 102 provides an access point to the EPC160 for a UE 104. Examples of UEs 104 include a cellular phone, a smartphone, a session initiation protocol (SIP) phone, a laptop, a personaldigital assistant (PDA), a satellite radio, a global positioning system,a multimedia device, a video device, a digital audio player (e.g., MP3player), a camera, a game console, a tablet, a smart device, a wearabledevice, or any other similar functioning device. The UE 104 may also bereferred to as a station, a mobile station, a subscriber station, amobile unit, a subscriber unit, a wireless unit, a remote unit, a mobiledevice, a wireless device, a wireless communications device, a remotedevice, a mobile subscriber station, an access terminal, a mobileterminal, a wireless terminal, a remote terminal, a handset, a useragent, a mobile client, a client, or some other suitable terminology.

Referring again to FIG. 1, in certain aspects, the eNB 102 may beconfigured to determine different transmission rates for differenttransmission directions, and to transmit initial access signals in thedifferent transmission directions based on the transmission rates forthe different transmission directions. (198).

FIG. 2A is a diagram 200 illustrating an example of a DL frame structurein LTE. FIG. 2B is a diagram 230 illustrating an example of channelswithin the DL frame structure in LTE. FIG. 2C is a diagram 250illustrating an example of an UL frame structure in LTE. FIG. 2D is adiagram 280 illustrating an example of channels within the UL framestructure in LTE. Other wireless communication technologies may have adifferent frame structure and/or different channels. In LTE, a frame (10ms) may be divided into 10 equally sized subframes. Each subframe mayinclude two consecutive time slots. A resource grid may be used torepresent the two time slots, each time slot including one or more timeconcurrent resource blocks (RBs) (also referred to as physical RBs(PRBs)). The resource grid is divided into multiple resource elements(REs). In LTE, for a normal cyclic prefix, an RB contains 12 consecutivesubcarriers in the frequency domain and 7 consecutive symbols (for DL,OFDM symbols; for UL, SC-FDMA symbols) in the time domain, for a totalof 84 REs. For an extended cyclic prefix, an RB contains 12 consecutivesubcarriers in the frequency domain and 6 consecutive symbols in thetime domain, for a total of 72 REs. The number of bits carried by eachRE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry DL reference (pilot)signals (DL-RS) for channel estimation at the UE. The DL-RS may includecell-specific reference signals (CRS) (also sometimes called common RS),UE-specific reference signals (UE-RS), and channel state informationreference signals (CSI-RS). FIG. 2A illustrates CRS for antenna ports 0,1, 2, and 3 (indicated as R₀, R₁, R₂, and R₃, respectively), UE-RS forantenna port 5 (indicated as R₅), and CSI-RS for antenna port 15(indicated as R). FIG. 2B illustrates an example of various channelswithin a DL subframe of a frame. The physical control format indicatorchannel (PCFICH) is within symbol 0 of slot 0, and carries a controlformat indicator (CFI) that indicates whether the physical downlinkcontrol channel (PDCCH) occupies 1, 2, or 3 symbols (FIG. 2B illustratesa PDCCH that occupies 3 symbols). The PDCCH carries downlink controlinformation (DCI) within one or more control channel elements (CCEs),each CCE including nine RE groups (REGs), each REG including fourconsecutive REs in an OFDM symbol. A UE may be configured with aUE-specific enhanced PDCCH (ePDCCH) that also carries DCI. The ePDCCHmay have 2, 4, or 8 RB pairs (FIG. 2B shows two RB pairs, each subsetincluding one RB pair). The physical hybrid automatic repeat request(ARQ) (HARQ) indicator channel (PHICH) is also within symbol 0 of slot 0and carries the HARQ indicator (HI) that indicates HARQ acknowledgement(ACK)/negative ACK (NACK) feedback based on the physical uplink sharedchannel (PUSCH). The primary synchronization channel (PSCH) is withinsymbol 6 of slot 0 within subframes 0 and 5 of a frame, and carries aprimary synchronization signal (PSS) that is used by a UE to determinesubframe timing and a physical layer identity. The secondarysynchronization channel (SSCH) is within symbol 5 of slot 0 withinsubframes 0 and 5 of a frame, and carries a secondary synchronizationsignal (SSS) that is used by a UE to determine a physical layer cellidentity group number. Based on the physical layer identity and thephysical layer cell identity group number, the UE can determine aphysical cell identifier (PCI). Based on the PCI, the UE can determinethe locations of the aforementioned DL-RS. The physical broadcastchannel (PBCH) is within symbols 0, 1, 2, 3 of slot 1 of subframe 0 of aframe, and carries a master information block (MIB). The MIB provides anumber of RBs in the DL system bandwidth, a PHICH configuration, and asystem frame number (SFN). The physical downlink shared channel (PDSCH)carries user data, broadcast system information not transmitted throughthe PBCH such as system information blocks (SIBs), and paging messages.

As illustrated in FIG. 2C, some of the REs carry demodulation referencesignals (DM-RS) for channel estimation at the eNB. The UE mayadditionally transmit sounding reference signals (SRS) in the lastsymbol of a subframe. The SRS may have a comb structure, and a UE maytransmit SRS on one of the combs. The SRS may be used by an eNB forchannel quality estimation to enable frequency-dependent scheduling onthe UL. FIG. 2D illustrates an example of various channels within an ULsubframe of a frame. A physical random access channel (PRACH) may bewithin one or more subframes within a frame based on the PRACHconfiguration. The PRACH may include six consecutive RB pairs within asubframe. The PRACH allows the UE to perform initial system access andachieve UL synchronization. A physical uplink control channel (PUCCH)may be located on edges of the UL system bandwidth. The PUCCH carriesuplink control information (UCI), such as scheduling requests, a channelquality indicator (CQI), a precoding matrix indicator (PMI), a rankindicator (RI), and HARQ ACK/NACK feedback. The PUSCH carries data, andmay additionally be used to carry a buffer status report (BSR), a powerheadroom report (PHR), and/or UCI.

FIG. 3 is a block diagram of an eNB 310 in communication with a UE 350in an access network. In the DL, IP packets from the EPC 160 may beprovided to a controller/processor 375. The controller/processor 375implements layer 3 and layer 2 functionality. Layer 3 includes a radioresource control (RRC) layer, and layer 2 includes a packet dataconvergence protocol (PDCP) layer, a radio link control (RLC) layer, anda medium access control (MAC) layer. The controller/processor 375provides RRC layer functionality associated with broadcasting of systeminformation (e.g., MIB, SIBs), RRC connection control (e.g., RRCconnection paging, RRC connection establishment, RRC connectionmodification, and RRC connection release), inter radio access technology(RAT) mobility, and measurement configuration for UE measurementreporting; PDCP layer functionality associated with headercompression/decompression, security (ciphering, deciphering, integrityprotection, integrity verification), and handover support functions; RLClayer functionality associated with the transfer of upper layer packetdata units (PDUs), error correction through ARQ, concatenation,segmentation, and reassembly of RLC service data units (SDUs),re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; andMAC layer functionality associated with mapping between logical channelsand transport channels, multiplexing of MAC SDUs onto transport blocks(TBs), demultiplexing of MAC SDUs from TBs, scheduling informationreporting, error correction through HARQ, priority handling, and logicalchannel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370implement layer 1 functionality associated with various signalprocessing functions. Layer 1, which includes a physical (PHY) layer,may include error detection on the transport channels, forward errorcorrection (FEC) coding/decoding of the transport channels,interleaving, rate matching, mapping onto physical channels,modulation/demodulation of physical channels, and MIMO antennaprocessing. The TX processor 316 handles mapping to signalconstellations based on various modulation schemes (e.g., binaryphase-shift keying (BPSK), quadrature phase-shift keying (QPSK),M-phase-shift keying (M-PSK), M-quadrature amplitude modulation(M-QAM)). The coded and modulated symbols may then be split intoparallel streams. Each stream may then be mapped to an OFDM subcarrier,multiplexed with a reference signal (e.g., pilot) in the time and/orfrequency domain, and then combined together using an Inverse FastFourier Transform (IFFT) to produce a physical channel carrying a timedomain OFDM symbol stream. The OFDM stream is spatially precoded toproduce multiple spatial streams. Channel estimates from a channelestimator 374 may be used to determine the coding and modulation scheme,as well as for spatial processing. The channel estimate may be derivedfrom a reference signal and/or channel condition feedback transmitted bythe UE 350. Each spatial stream may then be provided to a differentantenna 320 via a separate transmitter 318TX. Each transmitter 318TX maymodulate an RF carrier with a respective spatial stream fortransmission.

At the UE 350, each receiver 354RX receives a signal through itsrespective antenna 352. Each receiver 354RX recovers informationmodulated onto an RF carrier and provides the information to the receive(RX) processor 356. The TX processor 368 and the RX processor 356implement layer 1 functionality associated with various signalprocessing functions. The RX processor 356 may perform spatialprocessing on the information to recover any spatial streams destinedfor the UE 350. If multiple spatial streams are destined for the UE 350,they may be combined by the RX processor 356 into a single OFDM symbolstream. The RX processor 356 then converts the OFDM symbol stream fromthe time-domain to the frequency domain using a Fast Fourier Transform(FFT). The frequency domain signal comprises a separate OFDM symbolstream for each subcarrier of the OFDM signal. The symbols on eachsubcarrier, and the reference signal, are recovered and demodulated bydetermining the most likely signal constellation points transmitted bythe eNB 310. These soft decisions may be based on channel estimatescomputed by the channel estimator 358. The soft decisions are thendecoded and deinterleaved to recover the data and control signals thatwere originally transmitted by the eNB 310 on the physical channel. Thedata and control signals are then provided to the controller/processor359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with a memory 360 thatstores program codes and data. The memory 360 may be referred to as acomputer-readable medium. In the UL, the controller/processor 359provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, and control signalprocessing to recover IP packets from the EPC 160. Thecontroller/processor 359 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DLtransmission by the eNB 310, the controller/processor 359 provides RRClayer functionality associated with system information (e.g., MIB, SIBs)acquisition, RRC connections, and measurement reporting; PDCP layerfunctionality associated with header compression/decompression, andsecurity (ciphering, deciphering, integrity protection, integrityverification); RLC layer functionality associated with the transfer ofupper layer PDUs, error correction through ARQ, concatenation,segmentation, and reassembly of RLC SDUs, re-segmentation of RLC dataPDUs, and reordering of RLC data PDUs; and MAC layer functionalityassociated with mapping between logical channels and transport channels,multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs,scheduling information reporting, error correction through HARQ,priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a referencesignal or feedback transmitted by the eNB 310 may be used by the TXprocessor 368 to select the appropriate coding and modulation schemes,and to facilitate spatial processing. The spatial streams generated bythe TX processor 368 may be provided to different antenna 352 viaseparate transmitters 354TX. Each transmitter 354TX may modulate an RFcarrier with a respective spatial stream for transmission.

The UL transmission is processed at the eNB 310 in a manner similar tothat described in connection with the receiver function at the UE 350.Each receiver 318RX receives a signal through its respective antenna320. Each receiver 318RX recovers information modulated onto an RFcarrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 thatstores program codes and data. The memory 376 may be referred to as acomputer-readable medium. In the UL, the controller/processor 375provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover IP packets from the UE 350. IP packets from thecontroller/processor 375 may be provided to the EPC 160. Thecontroller/processor 375 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations.

Wireless communication systems may employ narrow bandwidths and highfrequency carriers. For example an mmW system may be utilized forwireless communication at a high transmission rate (e.g., transmittingfrequently). In mmW systems, when the carrier frequency is high (e.g.,28 GHz), path loss may be high. For example, the carrier frequency formmW communication may be 10 times higher than a carrier frequency forother types of wireless communication. Thus, for example, the mmW systemmay experience path loss that is approximately 20 dB higher than othertypes of wireless communication cases at lower frequencies. To mitigatethe higher path loss in mmW systems, a base station may performtransmission in a directional manner by beam-forming the transmission tofocus the transmission in a particular direction.

If the carrier frequency for wireless communication is at a higherfrequency, the wavelength of the carrier is shorter. A shorterwavelength may allow a higher number of antennas to be implementedwithin a given antenna array length than a number of antennas that canbe implemented when a lower carrier frequency is used. Therefore, in themmW system (using a higher carrier frequency), a higher number ofantennas may be used in a base station and/or a UE. For example, the BSmay have 128 or 256 antennas and the UE may have 8, 16 or 24 antennas.With the higher number of antennas, a beam-forming technique may be usedto digitally change the direction of a beam by applying different phasesto different antennas. Because beam-forming in an mmW system may providea narrow beam with increased gain at the receiver, the base station mayutilize the narrow beam to transmit a synchronization signal in variousdirections using multiple narrow beams to provide coverage over a widerarea.

Due to the directional nature of a beam-formed beam, for a UE to obtaina desirable gain in the mmW system, the beam from the base stationshould be focused directly at a UE such that the direction of the beamaligns with the location of the UE in order for the UE to have anacceptable signal characteristic (e.g., signal strength, SNR, gain). Ifthe direction of the beam is not properly aligned, the antenna gain atthe UE may be undesirably low (e.g., resulting in low SNR, high blockerror rates, etc.). Further, when the UE enters the mmW system (e.g., byentering a coverage area of the mmW system or by being activated) andreceives transmitted data from the base station over the mmW system, thebase station should be able to determine the best beam(s) for mmWcommunication with the particular UE. Thus, the base station maytransmit beam reference signals (BRSs) using beams in multipledirections so that the UE may identify the best beam of the beamsreceived from the base station (e.g., in multiple directions) based onmeasurements of the BRSs. In the mmW communication system, the basestation may also transmit a primary synchronization signal (PSS), asecondary synchronization signal (SSS), an extended synchronizationsignal (ESS), and PBCH signals for synchronization and for broadcastingsystem information. In the mmW communication system, such signals may betransmitted directionally via multiple beams to provide a wider coveragearea.

If there are multiple antenna ports (multiple sets of antennas) in thebase station, the base station may transmit multiple beams per symbol.For example, the base station may use multiple antenna ports in a cellspecific manner in a first symbol of a synchronization sub-frame tosweep in multiple directions. The base station may then sweep inmultiple directions using the multiple antenna ports in a cell specificmanner in another symbol of the synchronization sub-frame. Each antennaport may include a set of antennas. For example, an antenna portincluding a set of antennas (e.g., 64 antennas) may transmit one beam,and several antenna ports may transmit multiple beams, each in adifferent direction. Thus, if there are four antenna ports, the fourantenna ports may sweep through four directions (e.g., transmit fourbeams in four different directions). FIGS. 4A and 4B show examplediagrams illustrating the base station sweeping in multiple directionsin a first symbol and a second symbol, respectively. As shown in FIGS.4A and 4B, the base station may sweep in different directions in eachsymbol, e.g., the angular/directional range of the beams for the examplein FIG. 4A is different from the angular/directional range of the beamsfor the example in FIG. 4B. FIG. 4A is an example diagram 400illustrating transmission of beams in a first symbol. A base station 402in this example has four antenna ports, and may transmit four beams 412,414, 416, and 418 in four different directions in the first symbol. FIG.4B is an example diagram 450 illustrating transmission of beams in asecond symbol. Since the base station 402 has four antenna ports, fourbeams 462, 464, 466, and 468 may be transmitted in four differentdirections in the second symbol. The beams transmitted by the basestation during the same symbol may not be adjacent with each other.

FIG. 5 is an example diagram 500 illustrating a synchronization subframestructure for a millimeter wave communication system. Thesynchronization subframe may be divided into 14 symbols, e.g., fromsymbol 0 to symbol 13. Within each symbol, 100 subcarriers may betransmitted, where the first 41 RBs are used to carry BRSs and PBCHs,the next 18 RBs are used to carry an SSS, a PSS, and an ESS, and thenext 41 RBs are used to carry BRSs and PBCHs.

The beam transmitted by each antenna port may change from symbol tosymbol. As discussed above, for example, for a first symbol, four beamsfrom four antenna ports of the base station may cover a first angularrange (e.g., as illustrated in FIG. 4A), while four beams from the fourantenna ports may cover a second angular range for a different symbol(e.g., as illustrated in FIG. 4B). For example, the base station mayhave 1, 2, 4, or 8 active antenna ports. Within each symbol, the basestation may transmit one or more of a PSS, an SSS, an ESS, a PBCH, and aBRS on each subcarrier. Each of the PSS, the ESS, the SSS, and the PBCHis transmitted by all antenna ports of the base station on the samesubcarriers throughout different symbols of the synchronizationsubframe. The PSS and SSS may be used to obtain the cell identity andthe subframe level synchronization. However, PSS and SSS may not providesufficient information to identify a symbol of the subframe. Therefore,the ESS may be used to indicate a particular symbol. The contents of theESS may change from symbol to symbol. Therefore, the ESS may be used toindicate a symbol to enable the UE to identify a particular symbol indexwithin the subframe. The ESS may be similar in structure with othersynchronization signals such as the PSS and the SSS. For example, theESS as well as the PSS may be based on a Zadoff Chu sequence (e.g., withlength 71). However, unlike the PSS, the Zadoff Chu sequence of each ESSmay be cyclically shifted by a different amount, depending on theparticular symbol. For example, for each different symbol, the basestation cyclically shifts the Zadoff Chu sequence by a different amountto generate a different ESS for each different symbol. When the UEreceives the ESS, the UE may be able to determine the symbol index basedon the amount of the cyclic shift of the Zadoff Chu sequence of the ESS.If more than one base station, each in different cells, transmit ESSs,the UE may not be able to determine which base station transmitted theESS. Thus, the Zadoff Chu sequence in the ESS may include cell-specificroots (e.g., by the corresponding base station) that are specific to aparticular cell. The cell-specific roots, may enable the UE to identifywhich base station transmitted the ESS. The Zadoff Chu sequence in theESS may also be scrambled using a cell-specific sequence, such that theUE may be able to identify which base station transmitted the ESS, basedon the cell-specific sequence.

In an aspect, the angular space of the coverage area of a cell may bedivided into three sectors, where each sector covers 120 degrees. A basestation may provide coverage for one or more sectors. Each symbol of thesynchronization subframe may be associated with a different range indirection/angle. For example, the 14 symbols may collectively cover 120degrees (one sector). In one example, when there are 14 symbols (thus 14direction ranges) per subframe and there are 4 antenna ports, the basestation may transmit beams in 56 (14×4) different directions. In anotherexample, the symbols within a subframe may cover the angular range morethan once. In such an example, if there are 14 symbols within asubframe, the first seven symbols may cover 120 degrees, and then thenext seven symbols may cover the same 120 degrees.

FIG. 6 is an example diagram 600 illustrating transmission of initialaccess signals. The base station may transmit one or more initial accesssignals (such as a PSS, an SSS, a PBCH signal, a BRS signal) twicewithin one radio frame. In this example, because the radio frame is 10milliseconds long, the base station may transmit initial access signalsevery 5 milliseconds. In particular, the base station may use a firstchannel 612 within a radio frame to transmit the initial access signalsa first time, and then use a second channel 616 to transmit the initialaccess signals a second time. A RACH signal 614 may be transmittedbetween the first channel 612 and the second channel 616. A RACH signal618 may be transmitted after the second channel 616. In this example,the base station processes the initial access signals such that there iscyclic prefix between the initial access signals in the processedinitial access signal 652. The initial access signals may be processedby time-division multiplexing the initial access signals. In the examplediagram 600, the initial access signals may be processed bytime-division multiplexing the PSS, the SSS, and the PBCH. In this case,because there are fourteen symbols, transmission of the processedinitial access signal 652 may be performed fourteen times viabeam-forming in fourteen directions in a sweeping manner (e.g., to coverthe entire sector). The tone spacing for each of the initial accesssignals in the processed initial access signal 652 is 120 kHz. The PBCHsignal may be frequency-division multiplexed with a BRS and/or an ESS.

As discussed above, path loss (e.g., free space path loss) increases asa carrier frequency increases. The free space path loss is path lossthat results from a line-of-sight path through free space (e.g., air)for a signal transmission, with no obstacles nearby to cause reflectionor diffraction of the signal. In an mmW system utilizing beam-formedbeams transmitted in various directions, if a UE is not aligned with adirection of a beam from the base station, the antenna gain at a UE forthe beam may be reduced and higher free space path loss may result. Inaddition, communication in an mmW system may suffer from additionalnon-line-of-sight path losses that are not caused by the UE not beingaligned with the direction of a beam. Such non-line-of-sight losses mayinclude, for example, diffraction loss (e.g., signal loss caused by anobject such as a building blocking a signal), penetration loss (e.g.,signal loss due to a signal penetrating an object such as a wall),oxygen absorption loss (e.g., signal loss caused by the atmosphere),foliage loss (e.g., signal loss when a signal passes through leaves),etc. During an initial access stage where a UE and a base stationcommunicate with each other to discover each other and establishconnection each other, the base station and UE may be configured tominimize various types of path loss describe above.

During an initial access stage, a base station may transmit initialaccess signals (e.g., a PSS, an SSS, an ESS, a PBCH, a BRS) to the UE toestablish a connection between the base station and the UE, and the UEmay transmit random access signals (e.g., random access channel (RACH)signals) to the base station. For example, during a synchronizationperiod and a random access period in the initial access stage, the basestation may utilize at least one of the following two beamformingapproaches to compensate for the high free space path loss andadditional non-line-of-sight losses. According to one approach, the basestation may divide the entire angular region surrounding the basestation into multiple angular regions, and may transmit the initialaccess signals and receive the random access signals in a beamformedmanner (e.g., in a directional manner), sweeping through the angularregions in various directions (e.g., in an azimuth direction and/or anelevation direction). According to another approach, the base stationmay transmit the initial access signals and may receive the randomaccess signals for a longer duration, using a pseudo-omni beam. Thepseudo-omni beam is a beam that covers a large angular regionsurrounding the base station with uniform signal strength, which isdifferent from beam-forming in a directional manner.

The beam sweeping in different directions with different beams may beadvantageous in that different transmission rates (e.g., differentfrequencies of transmission) may be used for different beams indifferent directions. If the base station is configured to transmitmultiple beams in different directions (in a directional manner), thebase station may transmit initial access signals via the multiple beamsin the different directions based on different transmission rates. Forexample, the base station may transmit the initial access signal morefrequently (e.g., higher transmission rate) in one direction and maytransmit the initial access signal less frequently (e.g., lowertransmission rate) in another direction. Because different transmissionrates may be used to transmit the initial access signals in differenttransmission directions, the base station may be configured toprioritize some directions over other directions, e.g., by utilizing ahigher transmission rate for some directions (e.g., higher prioritydirections) and a lower transmission rate for other directions (e.g.,lower priority directions). According to an aspect of the disclosure,the base station may configure a transmission rate of an initial accesssignal from the base station for a particular transmission direction ofa beam (or a group of beams), and transmit the initial access signalusing the configured transmission rate for the particular transmissiondirection. In an aspect, the base station may determine a transmissionrate for a particular transmission direction based on a number of UEsaligned in a particular transmission direction. Thus, the base stationmay identify particular directions where more UEs are present or arelikely to be present and may transmit initial access signals in suchparticular directions more frequently (e.g., with a higher transmissionrate). For example, if the base station determines that more UEs arepresent in a particular angular region, then the base station maytransmit initial access signals more frequently in transmissiondirections that are within the particular angular region. Similarly, inan aspect, if the base station identifies particular directions wheremore UEs are absent or likely to be absent, the base station maytransmit the initial access signals less frequently in such particulardirections (e.g., with a lower transmission rate) or may avoidtransmitting initial access signals in such particular directions. Forexample, the base station may determine whether more UEs are present ina particular direction by receiving certain signals from UE(s), asdiscussed more in detail infra.

In one use example, if an mmW base station is located near a subwaystation, the mmW base station may transmit initial access signals morefrequently in transmission directions toward an entry area and/or anexist area of the subway station because more UEs, e.g., UEs carried bypeople, are expected in the entry area and/or the exit area. In anotheruse example, if an mmW base station is located near absorber panels thatare not capable of reflecting signals, the mmW base station may beconfigured to transmit initial access signals less frequently intransmission directions toward the absorber panels because the absorberpanels cannot reflect the initial access signals to UEs that are locatedin opposing directions from the absorber panels. For example, becausethe absorber panels may prevent the base station's signals fromdispersing in different directions by absorbing the base station'ssignals, transmitting signals at a higher transmission rate (e.g., morefrequently) toward the absorber panels may not be advantageous.

In an aspect, the base station may receive information regardingtransmission rates for different transmission directions from a networkentity. The network entity may be a centralized controller or a masterbase station in a centralized network, where the master base station isconnected to multiple base stations to manage the multiple basestations. The master base station may include information regarding anumber of UEs aligned in each of the plurality of transmissiondirections. Based on the information regarding the transmission ratesreceived from the network entity, the base station may determine thetransmission rates for different transmission directions.

FIGS. 7A and 7B are example diagrams illustrating a first scenario witha uniform transmission rate across various transmission directions. FIG.7A is an example diagram 700 illustrating transmission of beams in asymbol, according to the first scenario. Base station 702 may have fourantenna ports, and thus may transmit four beams including a first beam712, a second beam 714, a third beam 716, and a fourth beam 718 in fourdifferent transmission directions in the symbol. In the example diagram700, a first UE 722, a second UE 724, a third UE 726, and a fourth UE728 are uniformly distributed across the four different transmissiondirections of the first, second, third, and fourth beams 712, 714, 716,and 718. Thus, the base station 702 may configure a transmission rate ofan initial access signal for each of the four different transmissiondirections uniformly. FIG. 7B is an example diagram 750 illustratingresource usage for transmissions of initial access signals in differenttransmission directions, according to the first scenario. In the examplediagram 750, time slot 0 is used to transmit the initial access signalin the first transmission direction via the first beam 712, time slot 1is used to transmit the initial access signal in the second transmissiondirection via the second beam 714, time slot 2 is used to transmit theinitial access signal in the third transmission direction via the thirdbeam 716, and time slot 3 is used to transmit the initial access signalin the fourth transmission direction via the fourth beam 718. Further,time slot 4 is used to transmit the initial access signal in the firsttransmission direction via the first beam 712, time slot 5 is used totransmit the initial access signal in the second transmission directionvia the second beam 714, time slot 6 is used to transmit the initialaccess signal in the third transmission direction via the third beam716, and time slot 7 is used to transmit the initial access signal inthe fourth transmission direction via the fourth beam 718. Thus, in thefirst scenario, the transmission rate of initial access signals is thesame for all four directions. Such a pattern of transmitting initialaccess signals in the four transmission directions may be repeated.

FIGS. 8A and 8B are example diagrams illustrating a second scenario withdifferent transmission rates for different groups of transmissiondirections. FIG. 8A is an example diagram 800 illustrating transmissionof beams in a symbol, according to the second scenario. A base station802 may have four antenna ports, and may transmit four beams including afirst beam 812, a second beam 814, a third beam 816, and a fourth beam818 in four different transmission directions in the symbol. In theexample diagram 800, a first UE 822, a second UE 824, and a third UE 826are located in an angular region where the first beam 812 in the firsttransmission direction and the second beam 814 in the secondtransmission direction are transmitted. A fourth UE 828 is located in anangular region where the third beam 816 in the third transmissiondirection and the fourth beam 818 in the fourth transmission directionare transmitted. Thus, the base station 802 may configure a highertransmission rate of an initial access signal for each of the first andsecond transmission directions, and configure a lower transmission rateof an initial access signal for each of the third and fourthtransmission directions. FIG. 8B is an example diagram 850 illustratingresource usage for transmissions of initial access signals in differenttransmission directions, according to the second scenario. In theexample diagram 850, time slot 0 is used to transmit the initial accesssignal in the first transmission direction via the first beam 812, timeslot 1 is used to transmit the initial access signal in the secondtransmission direction via the second beam 814, time slot 2 is used totransmit the initial access signal in the third transmission directionvia the third beam 816, and time slot 3 is used to transmit the initialaccess signal in the fourth transmission direction via the fourth beam818. Then, time slot 4 is used to transmit the initial access signal inthe first transmission direction via the first beam 812, time slot 5 isused to transmit the initial access signal in the second transmissiondirection via the second beam 814, time slot 6 is used to transmit theinitial access signal in the first transmission direction via the firstbeam 812, and time slot 7 is used to transmit the initial access signalin the second transmission direction via the second beam 814. Thus,within the eight time slots (time slots 0-7), the base station isconfigured to transmit in the first and second transmission directionswith a transmission rate that is three times higher than a transmissionrate for transmitting in the third and fourth transmission directionsbecause more UEs are present in the first and second transmissiondirections than in the third and fourth transmission directions. Such apattern of transmitting initial access signals in the four transmissiondirections may be repeated.

In an aspect, the base station may determine a transmission rate for aparticular direction based on a number of random access signal that thebase station has received in the particular direction. The random accesssignal may be transmitted by a UE, and may be a RACH signal. Forexample, if more random access signals are received in a particulardirection, the base station may determine that more UEs are present inthe particular direction. In an aspect, the base station may consider apast history of reception of random access signals at the base station,and may determine whether more random access signals are received in aparticular direction than another direction. If the base stationreceives more random access signals in a particular direction, the basestation may configure a transmission rate for the particular directionto be higher than a transmission rate of another direction.

In an aspect, the base station may determine the a transmission rate ina particular transmission direction based on a number of schedulingrequests that the base station receives in the particular transmissiondirection. The scheduling request may be transmitted by a UE. Thus, forexample, if more scheduling requests are received in a particulardirection, the base station may determine that more UEs are present inthe particular direction. Thus, if the base station receives morescheduling requests in a particular direction than another direction,the base station may configure a transmission rate for the particulardirection to be higher than a transmission rate of another direction.

In an aspect, the base station may determine the a transmission rate ina particular transmission direction based on a number of beam trainingrequests that the base station receives in the particular transmissiondirection. The beam training request may be transmitted by a UE. Thus,example, if more beam training requests are received in a particulardirection, the base station may determine that more UEs are present inthe particular direction. Thus, if the base station receives more beamtraining requests in a particular direction than another direction, thebase station may configure a transmission rate for the particulardirection to be higher than a transmission rate of another direction.

In an aspect, the base station may determine the a transmission rate ina particular transmission direction based on a number of beam recoveryrequests that the base station receives in the particular transmissiondirection. The beam recovery request may be transmitted by a UE. Thus,example, if more beam recovery requests are received in a particulardirection, the base station may determine that more UEs are present inthe particular direction. Thus, if the base station receives more beamrecovery requests in a particular direction than another direction, thebase station may configure a transmission rate for the particulardirection to be higher than a transmission rate of another direction.

In an aspect, the base station may transmit the base station'stransmission rates for different transmission directions to one or moreUEs. In one approach, the base station may transmit all of the basestation's transmission rates for different transmission directions bybroadcasting the base station's transmission rates. In another approach,the base station may transmit all of the base station's transmissionrates for different transmission directions to a UE via a unicasttransmission. In another approach, the base station may transmit, toeach UE, the base station's transmission rate(s) for transmissiondirection(s) with which each UE is aligned, via a unicast transmission.When a unicast transmission is used, the base station may transmit thebase station's transmission rate(s) using RRC signaling and/or a randomaccess response (e.g., RACH message 2 (MSG2)). In an aspect, the basestation may transmit the information about transmission rates fordifferent transmission directions via a MIB and/or a SIB. The MIB may betransmitted via a PBCH. The SIB may be transmitted via at least one of aPBCH, an extended PBCH, or RRC signaling.

When the UE receives base station's transmission rate(s), the UE maydetermine the base station's transmission rate(s) for a particulartransmission direction that is aligned with the UE. In one example, theUE may determine that a particular transmission direction of the basestation is aligned with the UE if a signal strength or an SNR is thehighest in the particular transmission direction among transmissiondirections of the base station. In an aspect, the base station mayconvey to the UE information about the particular direction aligned withthe UE and a transmission rate for the particular direction. Based onthe base station's transmission rate(s), a UE may configure certaincommunication settings for communicating with the base station. In anaspect, the UE may configure an activation time to indicate how often towake up to activate a connection of the UE with the base station, basedon a transmission rate of the base station for a particular transmissiondirection aligned with the UE. For example, the UE may determine to wakeup less often to conserve power if the transmission rate of the basestation is lower in the particular transmission direction with which theUE is aligned. On the other hand, the UE may determine to wake up moreoften if the transmission rate of the base station is higher for theparticular transmission direction with which the UE is aligned. In anaspect, the UE may activate the connection with the base station inresponse to receiving paging information from the base station.

FIG. 9 is a diagram 900 illustrating an example overall processaccording to an aspect of the disclosure. The example diagram 900involves communication among a UE 902, a base station 904, and a networkentity 906. The base station 904 may be an mmW base station capable ofcommunicating in a beam-formed manner (e.g., using directional beams).At 910, the base station 904 may receive, from the network entity 906,information about transmission rates for different transmissiondirections. At 912, the base station 904 may receive, from the UE 902,at least one of a random access signal, a scheduling request, a beamtraining request, or a beam recovery request. At 914, the base station904 may determine transmission rates of the base station for differenttransmission directions, where each different transmission directionrespectively corresponds with a different beam. The base station 904 maydetermine the transmission rates based on the information received fromthe network entity 906 and/or a number of random accesssignals/scheduling requests/beam training requests/beam recoveryrequests received from the UE 902 and other UEs in the transmissiondirection where the UE 902 is aligned. At 916, the base station maytransmit an initial access signal to the UE 902 based on a transmissionrate for the transmission direction aligned with the UE 902.

At 918, the base station may transmit the transmission rate(s) of thebase station for the transmission direction where the UE 902 is aligned.At 920, the UE 902 may determine, based on the received transmissionrate of the base station, an activation time at which the UE 902 wakesup to connect with the base station 904. At 922, the UE may wake up,based on the activation time, to connect with the base station 904 andcommunicate with the base station 904. In one example, after receivingthe transmission rate for the transmission direction aligned with the UE902, the UE 902 may enter a disconnected mode, being disconnected fromthe base station 904. Because the UE 902 has received the transmissionrate, UE 902 may determine a set of activation times based on thetransmission rate, such that the UE 902 may wake up from thedisconnected mode at the set of activation times, in order to establisha connection with the base station 904 (e.g., to enter a connected mode)and to receive the initial access signal from the base station 904.

For some communication conditions, assigning more beams of the basestation in a particular area may be desired. For example, UEs may not beuniformly located throughout a coverage area surrounding the basestation (e.g., in the coverage area of the base station). If more UEsare located in a particular area, assigning more beams for transmissionin the particular area may be desired to reach more UEs. In other words,assigning more beams in an area where UEs are more densely located thanin an area where UEs are less densely located may increase the number ofUEs reachable by the base station. Hence, in an aspect of thedisclosure, a base station may divide a coverage area surrounding thebase station into sub-regions (e.g., based on a density of UEs invarious portions of the coverage area), such that the base station maytransmit the initial access signal per sub-region (e.g., using a beamdirected in a direction corresponding to a respective sub-region). Thecoverage area surrounding the base station may be expressed in anangular range, and each sub-region may cover a respective portion of theangular range. The sub-regions may be non-uniform in size and/or portionof the angular range covered. In an aspect, the base station may dividethe surrounding area (e.g., coverage area) into non-uniform angularsub-regions.

The base station may have limited resources that allow utilization of acertain number of beams (e.g., simultaneously). Thus, a number of beamsallowed by the resources may determine a number of sub-regions in thesurrounding region (e.g., coverage area) of the base station. The basestation may assign one beam or one set of beams of the base station persub-region. In an aspect, the same number of beams or approximately thesame number of beams may be assigned to each sub-region. In an aspect,one beam may be assigned to each sub-region, and thus a number ofsub-regions may be the same as a number of beams. For example, if thebase station has sufficient resources for 3 beams to cover a surroundingregion, the base station may divide the surrounding region into threesub-regions and may assign one beam to each sub-region. In anotheraspect, more than one beam may be assigned to each sub-region. Forexample, if the base station is configured to divide the surroundingregion into three sub-regions and has sufficient resources for 6 beams,the base station may assign two beams to each sub-region. Thus, a numberof beams assigned per sub-region may be based on the number of beamsallowed by the resources and a number of sub-regions configured by thebase station. In an aspect, the base station may assign more than onebeam per sub-region if a number of beams allowed by the resources isgreater than a threshold, where the threshold is a maximum number ofsub-regions configured by the base station. For example, if thethreshold is 4 and a number of beams allowed by the resources is 7, thebase station may allocate 2 beams to each of three sub-regions and 1beam to a remaining sub-region. When assigning the beams to sub-regions,the base station may steer each beam such that a direction of each beamaligns with a corresponding sub-region. For example, if an angularsub-region exists between 0 and 60 degrees, the base station may steer abeam such that a direction of each beam aligns with a mid-point of acorresponding angular sub-region, which is at 30 degrees.

After assigning a beam or a set of beams to each sub-region, the basestation may steer beams of the base station in directions correspondingto the sub-regions such that each beam may be used to transmit theinitial access signal in the corresponding sub-region. For example, ifthe base station is configured to utilize three beams (e.g., viabeamforming) and the coverage area is divided into three sub-regions,the base station may assign one of three beams per sub-region. The beamsmay be beams of mmW communication, and thus the initial access signalmay be transmitted via a mmW transmission. The same transmission ratemay be used for each beam to transmit the initial access signal.

The base station may determine the sub-regions based on a number of UEsper unit angular region or per unit area. In particular, the basestation may determine sub-regions such that each sub-region hasapproximately the same number of UEs. That is, sub-regions may bedetermined such that a sub-region with a lower density of UEs may covera larger angular area than a sub-region with a higher density of UEs, inorder to provide each sub-region having approximately the same number ofUEs. Thus, the base station may determine a smaller sub-region for anarea with more UEs per area. For example, the base station may identifya first particular region where more UEs per area are present or arelikely to be present and may divide the first particular region intosmaller sub-regions. Because approximately the same number of beams isassigned to each sub-region, if the first particular region is dividedinto smaller sub-regions, more beams may be assigned to the firstparticular region with more UEs per area than another region havingfewer UEs per area and thus divided into larger sub-regions. Further,the base station may identify a second particular region where less UEsper area are present or are likely to be present and may divide thesecond particular region into one or more larger sub-regions, such thatless beams may be assigned to the second particular region with less UEsper area than another region having more UEs per area (e.g., higher UEdensity) and thus divided into more sub-regions of smaller size. Hence,in an aspect, the base station may determine sub-regions such that anumber of UEs per each sub-region is distributed through the differentsub-regions in a substantially uniform manner. In one example, if a basestation is capable of transmitting within a total angular range from −60degrees to 60 degrees (e.g., a total range of 120 degrees) and a firstset of three UE are located at an angular region covering −60 degrees to0 degree, a second set of three UEs are located in an angular regioncovering 0 degree to 30 degrees, and a third set of three UEs arelocated in an angular region covering 30 degrees to 60 degrees, the basestation may divide the total angular range to a first angular sub-regioncovering −60 degrees to 0 degree, a second angular sub-region covering 0degree to 30 degrees, and a third angular sub-region covering 30 degreesto 60 degrees, such that the same number of UEs is located in eachangular sub-region.

In an aspect, the base station may estimate a density of UEs in aparticular region based on a number of UE signals received by the basestation using a beam pointing in a direction corresponding to theparticular region. The direction corresponding to the particular regionmay be located at a mid-point of the angular coverage of the particularregion. For example, if the angular coverage of the particular regioncovers 0 degrees to 60 degrees, the mid-point of the particular regionis at 30 degrees, which is the beam direction of the beam providingcoverage to the particular region.

In an aspect, the base station may initially divide the coverage areasurrounding the base station into a set of unit angular ranges, suchthat the base station may estimate a number of UEs per unit angular rageand determine sizes of sub-regions based on the number of UEs per unitangular rage. Thus, different unit angular ranges cover different partsof the region surrounding the base station. Each unit angular range mayhave the same angular range size. For example, for each unit angularrange of a set of unit angular ranges, the base station may receive UEsignals from UEs while a beam of the base station points to a directioncorresponding to a corresponding unit angular range. For example, thebase station may estimate a number of UEs per unit angular range (e.g.,density of UEs) through various angular regions surrounding the basestation based on the UE signals received by the base station using abeam pointing to each unit angular rage. In one example, to receive UEsignals from UEs in different unit angular ranges, the base station maysweep in multiple directions corresponding to respective unit angularregions over the total area (e.g., the coverage area) surrounding thebase station, using beamforming, and may determine a number of UEsignals received in each of the multiple directions, where each of themultiple directions corresponds to a respective unit angular region. Forexample, if 10 unit angular regions of the same angular range size existwithin the total angular region surrounding the base station, the basestation may receive UE signals at 10 different directions respectivelycorresponding to 10 unit angular regions, to determine a number of UEsignals received per unit angular region in each unit angular region.Based on the number of UE signals received per unit angular region, thebase station may estimate a number of UEs in each unit angular region.Thus, based on the number of UE signals received per unit angularregion, the base station may determine which area is more dense withUEs, such that the base station may divide an area with a higher densityof UEs into smaller sub-regions. The UE signals may include at least oneof random access signals, scheduling requests, beam training requests,or beam recover requests, which are explained more in detail infra.

In an aspect, the base station may estimate a number of UEs in aparticular region (e.g., a particular unit angular range) based on anumber of random access signals that the base station has received fromthe particular region. The random access signal may be transmitted by aUE, and may be a RACH signal. For example, if more random access signalsare received from a particular region, the base station may determinethat more UEs are present in the particular region. In an aspect, thebase station may consider a past history of reception of random accesssignals at the base station, and may determine whether more randomaccess signals are received from a particular region than another regionbased on the past history. If the base station determines that the basestation receives more random access signals from a particular region,the base station may divide the particular region into a smallersub-regions than other regions. If the base station determines that thebase station receives less random access signals from a particularregion, the base station may divide the particular region into a largersub-regions than other regions.

In an aspect, the base station may determine a number of UEs in aparticular region (e.g., a particular unit angular range) based on anumber of scheduling requests that the base station received from theparticular region. The scheduling request may be transmitted by a UE. Inan aspect, the base station may consider a past history of reception ofscheduling requests at the base station, and may determine whether morescheduling requests are received from a particular region than anotherregion based on the past history. For example, if more schedulingrequests are received from a particular region, the base station maydetermine that more UEs are present in the particular region. Thus, ifthe base station receives more scheduling requests from a particularregion, the base station may divide the particular region into a smallersub-regions than other regions. If the base station determines that thebase station receives less scheduling requests from a particular region,the base station may divide the particular region into a largersub-regions than other regions.

In an aspect, the base station may determine a number of UEs in aparticular region (e.g., a particular unit angular range) based on anumber of beam training requests that the base station receives in theparticular region. The beam training request may be transmitted by a UE.In an aspect, the base station may consider a past history of receptionof beam training requests at the base station, and may determine whethermore beam training requests are received from a particular region thananother region based on the past history. For example, if more beamtraining requests are received from a particular region, the basestation may determine that more UEs are present in the particularregion. Thus, if the base station receives more beam training requestsfrom a particular region than another region, the base station maydivide the particular region into a smaller sub-regions than otherregions. If the base station determines that the base station receivesless beam training requests from a particular region, the base stationmay divide the particular region into a larger sub-regions than otherregions.

In an aspect, the base station may determine a number of UEs in aparticular region (e.g., a particular unit angular range) based on anumber of beam recovery requests that the base station receives in theparticular region. A beam recovery request may be transmitted by a UE.In an aspect, the base station may consider a past history of receptionof beam recovery requests at the base station, and may determine whethermore beam recovery requests are received from a particular region thananother region based on the past history. For example, if more beamrecovery requests are received from a particular region, the basestation may determine that more UEs are present in the particularregion. Thus, if the base station receives more beam recovery requestsfrom a particular region, the base station may divide the particularregion into sub-regions of smaller size than sub-regions for otherregions. If the base station determines that the base station receivesless beam recovery requests from a particular region, the base stationmay divide the particular region into sub-regions of greater size thanthe size of sub-regions for other regions having fewer UEs.

In an aspect, the base station may receive information regardingsub-regions of a surrounding region (e.g., coverage area) of the basestation from a network entity. The network entity may be a centralizedcontroller or a master base station in a centralized network, where themaster base station is connected to multiple base stations to manage themultiple base stations. In one example, the information received fromthe network entity may include a density or an expected density of UEsin each region of various regions surrounding the base station. Forexample, if the surrounding region of the base station is divided into aset of unit angular regions of the same size, the information from thebase station may provide a density or the expected density of UEs ineach unit angular region. Based on the information received from thenetwork entity, the base station may divide the surrounding region intomultiple sub-regions.

In one use example, if an mmW base station is located near a subwaystation, the mmW base station may determine that a surrounding regionincludes a first region covering the subway station and a second regionnot covering the subway station. Then, the base station may divide thefirst angular region covering the subway station into first sub-regionsof a first size and may divide the second angular region not coveringthe subway station into second sub-regions of a second size, where thefirst sub-regions are smaller than the second sub-regions. More UEs,e.g., carried by people, are expected in the entry area and/or the exitarea of the subway station. Therefore, the mmW base station maydetermine that the first angular region has a higher expected density ofUEs than the second angular region, and thus the mmW base station maydetermine the first sub-regions are smaller than the second sub-regionsbased on expected UE density.

FIG. 10 is an example diagram 1000 illustrating an approach to estimatea number of UEs in unit angular ranges. In the example diagram 1000 ofFIG. 10, the base station 1002 is capable of transmitting within asurrounding angular region (e.g., coverage region) between −60 degreesto 60 degrees. The base station may initially divide the surroundingangular region into a set of unit angular ranges of the same size, whereeach unit angular range is 30 degrees. The base station 1002 maytransmit and/or receive signals in a beamformed manner (e.g., via abeam), sweeping through various angular ranges between −60 degrees to 60degrees. In the example diagram 100 of FIG. 10, the base station 1002may receive signals in each direction corresponding to a respective unitangular range, where an angular difference between two adjacent unitangular ranges is 15 degrees. Thus, the base station 1002 may sweepbetween −60 degrees to 60 degrees with a beam using beamforming,receiving signals at every 15 degrees.

In particular, for a first unit angular range ranging from −60 to −30degrees, the base station 1002 may receive signals at a first beamdirection 1011 at −45 degrees, and may estimate that a number of UEs inthe first unit angular range is three (e.g., due to signals from UEs1034, 1036, and 1038) based on the received signals. For a second unitangular range ranging from −45 to −15 degrees, the base station 1002 mayreceive signals at a second beam direction 1012 at −30 degrees, and mayestimate that a number of UEs in the first unit angular range is four(e.g., due to signals from UEs 1030, 1032, 1034, and 1036) based on thereceived signals. For a third unit angular range ranging from −30 to 0degree, the base station 1002 may receive signals at a third beamdirection 1013 at −15 degrees, and may estimate that a number of UEs inthe first unit angular range is three (e.g., due to signals from UEs1028, 1030, and 1032) based on the received signals. For a fourth unitangular range ranging from −15 to 15 degrees, the base station 1002 mayreceive signals at a fourth beam direction 1014 at 0 degree, and mayestimate that a number of UEs in the first unit angular range is two(e.g., due to signals from UEs 1026 and 1028) based on the receivedsignals. For a fifth unit angular range ranging from 0 to 30 degrees,the base station 1002 may receive signals at a fifth beam direction 1015at 15 degree, and may estimate that a number of UEs in the first unitangular range is two (e.g., due to signals from UEs 1024 and 1026) basedon the received signals. For a sixth unit angular range ranging from 15to 45 degrees, the base station 1002 may receive signals at a sixth beamdirection 1016 at 30 degree, and may estimate that a number of UEs inthe first unit angular range is two (e.g., due to signals from UEs 1022and 1024) based on the received signals. For a seventh unit angularrange ranging from 30 to 60 degrees, the base station 1002 may receivesignals at a sixth beam direction 1017 at 45 degree, and may estimatethat a number of UEs in the first unit angular range is one (e.g., dueto a signal from the UE 1022) based on the received signals.

Thus, in the example of FIG. 10, the number of UEs per unit angularrange for the first, second and third unit angular ranges is three orfour, while the number of UEs per unit angular range for the fourth,fifth, sixth and seventh unit angular ranges is one or two. Because thefirst, second, and third unit angular ranges has more UEs per unitangular range than the other unit angular ranges, the base station 1002may determine that sub-regions within the angular region between −60degrees and 0 degree are smaller than another sub-region within theangular region between 0 and 60 degrees, as described infra, forexample.

FIG. 11 is an example diagram 1100 illustrating a non-uniformsub-regions surrounding a base station. In the example diagram 1100 ofFIG. 11, the base station 1002 is capable of transmitting within asurrounding angular region between −60 degrees to 60 degrees. The basestation 1002 has resources to utilize three beams, and thus, the basestation 1002 may divide the surrounding angular region into threesub-regions. The UEs 1022, 1024, and 1026 are sparsely distributed,while UEs 1028, 1030, 1032, 1034, 1036 and 1038 are densely populated.Thus, as discussed above in association with FIG. 10, the base station1002 may determine a larger sub-region for UEs 1022, 1024, and 1026 inthe angular region between 0 degree and 60 degrees, and smallersub-regions for UEs 1028, 1030, 1032, 1034, 1036 and 1038 in the angularregion between −60 degrees and 0 degree. In particular, the base station1002 may divide the surrounding angular region into a first sub-regioncovering an angular region between 0 and 60 degrees, a second sub-regioncovering an angular region between 0 and −30 degrees, and a thirdsub-region covering an angular region between −30 and −60 degrees.

In FIG. 11, the base station 1002 assigns a first beam 1112 to the firstsub-region, a second beam 1114 to the second sub-region, and a thirdbeam 1116 to the third sub-region. Thus, in the example diagram 1100 ofFIG. 11, the area surrounding the base station 1002 is divided intonon-uniform sub-regions such that one beam is assigned to eachsub-region, where three UEs are located in each sub-region. The basestation may steer each beam in a direction corresponding to a mid-pointangle in a corresponding sub-region. For example, the first beam 1112may be at 45 degrees to provide angular coverage from 0 degrees to 60degrees, the second beam 1114 may be at −15 degrees to provide angularcoverage from 0 degrees to −30 degrees, and the third beam 1116 may beat −45 degrees top provide angular coverage from −30 degrees to −60degrees. The base station 1002 may utilize the first beam 1112 totransmit the initial access signal in a direction corresponding to thefirst sub-region, may utilize the second beam 1114 to transmit theinitial access signal in a direction corresponding to the secondsub-region, and may utilize the third beam 1116 to transmit the initialaccess signal in a direction corresponding to the third sub-region. Inan aspect, the base station may use the same transmission rate for thefirst beam 1112, the second beam 1114, and the third beam 1116.

FIG. 12 is an example diagram 1200 illustrating a non-uniformsub-regions surrounding a base station. In the example diagram 1200 ofFIG. 12, the base station 1002 is capable of transmitting within asurrounding angular region between −60 degrees to 60 degrees. In theexample diagram 1200 of FIG. 12, the base station 1002 has resources toutilize five beams, and thus, the base station 1002 may divide thesurrounding angular region into five sub-regions. The UEs 1022, 1024,and 1026 are sparsely distributed, while UEs 1028, 1030, 1032, 1034,1036 and 1038 are densely populated. Thus, as discussed above inassociation with FIG. 10, the base station 1002 may determine a largestsub-region for UEs 1022, 1024, and 1026 in the angular region between 0degree and 60 degrees, and smaller sub-regions to cover the remainingUEs in different angular regions. In particular, the base station 1002may divide the surrounding angular region into a first sub-regioncovering an angular region between 60 and 0 degree, a second sub-regioncovering an angular region between 30 and −15 degrees, a thirdsub-region covering an angular region between 0 and −30 degrees, afourth sub-region covering an angular region between −15 and −45degrees, and a fifth sub-region covering an angular region between −30and −60 degrees. As illustrated in FIG. 12, different sub-regions mayoverlap with each other at least in part.

In FIG. 12, the base station 1002 assigns a first beam 1212 to the firstsub-region, a second beam 1214 to the second sub-region, a third beam1216 to the third sub-region, a fourth beam 1218 to the fourthsub-region, a fifth beam 1220 to the fifth sub-region. Thus, in theexample diagram 1200 of FIG. 12, the area surrounding the base station1002 is divided into non-uniform sub-regions such that one beam isassigned to each sub-region, where approximately three UEs are locatedin each sub-region. The base station may steer each beam in a directioncorresponding to a mid-point angle in a corresponding sub-region. Forexample, the first beam 1212 may be at 45 degrees to provide angularcoverage from 0 degrees to 60 degrees, the second beam 1214 may be at7.5 degrees to provide angular coverage from 30 degrees to −15 degrees,the third beam 1216 may be at −15 degrees to provide angular coveragefrom 0 degrees to −30 degrees, the fourth beam 1218 may be at −30degrees top provide angular coverage from −15 degrees to −45 degrees,and the fifth beam 1220 may be at −45 degrees top provide angularcoverage from −30 degrees to −60 degrees. The base station 1002 mayutilize the first beam 1212 to transmit the initial access signal in adirection corresponding to the first sub-region, may utilize the secondbeam 1214 to transmit the initial access signal in a directioncorresponding to the second sub-region, may utilize the third beam 1216to transmit the initial access signal in a direction corresponding tothe third sub-region, may utilize the fourth beam 1218 to transmit theinitial access signal in a direction corresponding to the fourthsub-region, and may utilize the fifth beam 1220 to transmit the initialaccess signal in a direction corresponding to the fifth sub-region. Inan aspect, the base station may use the same transmission rate for thefirst beam 1212, the second beam 1214, the third beam 1216, the fourthbeam 1218, and the fifth beam 1220.

FIG. 13 is a diagram 1300 illustrating an example overall processaccording to an aspect of the disclosure. The example diagram 1300involves communication among a UE 1302, a base station 1304, and anetwork entity 1306. The base station 1304 may be an mmW base stationcapable of communicating in a beam-formed manner (e.g., usingdirectional beams). At 1310, in an aspect, the base station 1304 mayreceive, from the network entity 1306, information about varioussub-regions of a surrounding region of the base station. At 1312, in anaspect, the base station 1304 may receive, from the UE 1302, UE signalsincluding at least one of a random access signal, a scheduling request,a beam training request, or a beam recovery request. At 1314, the basestation 1304 determines sub-regions for a region surrounding the basestation 1304 and divides the surrounding region into the sub-regions.The base station 1304 may determine the sub-regions based on theinformation received from the network entity 1306 and/or the number ofrandom access signals/scheduling requests/beam training requests/beamrecovery requests received from the UE 1302 and other UEs in variousregions. At 1306, the base station assigns each beam of the base stationto a respective sub-region of the sub-regions. At 1318, the base stationtransmits an initial access signal to the UE 1302 using a beamcorresponding to the sub-region in which the UE 1302 is located.

FIG. 14 is a flowchart 1400 of a method of wireless communication. Themethod may be performed by a base station (e.g., the base station 102,702, 802, 904, the apparatus 1602/1602′). In an aspect, at 1402, thebase station may receive, from a network entity, information about theplurality of transmission rates for the plurality of transmissiondirections. In an aspect, the transmission rates may be determined basedon the received information from the network entity. For example, asdiscussed supra, the base station may receive information regardingtransmission rates for different transmission directions from a networkentity. In an aspect, the network entity may be a centralized controlleror a second base station. For example, as discussed supra, the networkentity may be a centralized controller or a master base station in acentralized network, where the master base station is connected tomultiple base stations to manage the multiple base stations. In anaspect, the second base station may include information regarding anumber of user equipments aligned in each of the plurality oftransmission directions. For example, as discussed supra, the masterbase station may include information regarding a number of UEs alignedin each of the plurality of transmission directions.

In an aspect, at 1403, the base station may receive, from UEs, at leastone of random access signals, scheduling requests, beam trainingrequests, or beam recovery requests. For example, as discussed supra,the base station may receive at least one of random access signals,scheduling requests, beam training requests, or beam recovery requests(e.g., in a particular transmission direction).

At 1404, the base station determines a plurality of transmission rates,each transmission rate for a respective transmission direction of aplurality of transmission directions. In an aspect, each transmissiondirection of the plurality of transmission directions corresponds with arespective transmission beam of the base station. For example, asdiscussed supra, the base station may configure a transmission rate ofan initial access signal from the base station for a particulartransmission direction of a beam (or a group of beams).

In an aspect, the transmission rate for each transmission direction ofthe plurality of transmission directions may be determined based on anumber of user equipments aligned in the transmission direction. Forexample, as discussed supra, the base station may determine atransmission rate for a particular transmission direction based on anumber of UEs aligned in a particular transmission direction. In anaspect, the transmission rate for each transmission direction of theplurality of transmission directions may be determined based on a numberof random access signals received in the transmission direction. Forexample, as discussed supra, the base station may determine atransmission rate for a particular direction based on a number of randomaccess signal that the base station has received in the particulardirection. In an aspect, the transmission rate for each transmissiondirection of the plurality of transmission directions may be determinedbased on a number of scheduling requests received in the transmissiondirection. For example, as discussed supra, the base station maydetermine the a transmission rate in a particular transmission directionbased on a number of scheduling requests that the base station receivesin the particular transmission direction. In an aspect, the transmissionrate for each transmission direction of the plurality of transmissiondirections may be determined based on at least one of a number of beamtraining requests or a number of beam recovery requests. For example, asdiscussed supra, the base station may determine the a transmission ratein a particular transmission direction based on a number of beamtraining requests that the base station receives in the particulartransmission direction.

At 1406, the base station transmits at least one initial access signalin one or more transmission directions of the plurality of transmissiondirections based on the transmission rate of each transmission directionof the one or more transmission directions. For example, as discussedsupra, the base station may transmit the initial access signal using theconfigured transmission rate for the particular transmission direction.In an aspect, the at least one initial access signal may be transmittedvia a millimeter wave transmission. In an aspect, the at least oneinitial access signal may include at least one of a primarysynchronization signal, a secondary synchronization signal, an extendedsynchronization signal, a physical broadcast channel, or a beamreference signal. For example, as discussed supra, a base station maytransmit initial access signals (e.g., a PSS, an SSS, an ESS, a PBCH, aBRS) to the UE to establish a connection between the base station.

At 1408, the base station may transmit one or more transmission rates ofthe plurality of transmission rates for the plurality of transmissiondirections. For example, as discussed supra, the base station maytransmit the base station's transmission rates for differenttransmission directions to one or more UEs. In an aspect, the one ormore transmission rates may be transmitted via at least one of abroadcast transmission or a unicast transmission. In an aspect, the basestation may transmit the one or more transmission rates by transmitting,in a first transmission direction of the plurality of the transmissiondirections, a transmission rate corresponding to the first transmissiondirection via unicast transmission, where a UE is located in the firsttransmission direction. For example, as discussed supra, in oneapproach, the base station may transmit all of the base station'stransmission rates for different transmission directions by broadcastingthe base station's transmission rates. For example, as discussed supra,in another approach, the base station may transmit all of the basestation's transmission rates for different transmission directions to aUE via a unicast transmission. In an aspect, the one or moretransmission rates may be transmitted via at least one of a masterinformation block or a system information block. In such an aspect, themaster information block may be transmitted via a physical broadcastchannel. In such an aspect, the system information block may betransmitted via at least one of a physical broadcast channel, anextended physical broadcast channel, or RRC communication. For example,as discussed supra, the base station may transmit the information abouttransmission rates for different transmission directions via a MIBand/or a SIB. For example, as discussed supra, the MIB may betransmitted via a PBCH. For example, as discussed supra, the SIB may betransmitted via at least one of a PBCH, an extended PBCH, or RRCsignaling.

FIG. 15 is a flowchart 1500 of a method of wireless communication,according to an aspect of the disclosure. The method may be performed bya base station (e.g., the base station 102, 702, 1002, 1304, theapparatus 1602/1602′). In an aspect, at 1502, the base station mayreceive, from a network entity, information about the plurality ofsub-regions, where the region surrounding the base station may bedivided into the plurality of sub-regions based on the receivedinformation. For example, as discussed supra, the base station mayreceive information regarding sub-regions of a surrounding region of thebase station from a network entity. For example, as discussed supra,based on the information received from the network entity, the basestation may divide the coverage region surrounding the base station intomultiple sub-regions.

In an aspect, at 1504, the base station may receive one or more userequipment signals in each unit angular range of a plurality of unitangular ranges. For example, as discussed supra, for each unit angularrange of different unit angular ranges, the base station may receive UEsignals from UEs while a beam of the base station points to a directioncorresponding to a corresponding unit angular range.

At 1504, in an aspect, the base station may estimate a number of userequipments in each unit angular range of a plurality of unit angularranges within the region surrounding the base station, each unit angularrange covering a different angular region within the region surroundingthe base station and having a same angular range size. For example, asdiscussed supra, the base station may estimate a number of UEs per unitangular range (e.g., density of UEs) through various angular regionssurrounding the base station based on the UE signals received by thebase station using a beam pointing to each unit angular rage, where eachunit angular range may have the same angular range size.

In an aspect, the number of user equipments in each unit angular rangeof the plurality of unit angular ranges may be estimated based on anumber of the user equipment signals received in each unit angular rangeof the plurality of unit angular ranges. For example, as discussedsupra, based on the number of UE signals received per unit angularregion, the base station may estimate a number of UEs in each unitangular region. In such an aspect, the one or more user equipmentsignals may be received in each unit angular range via a beam sweepingthrough the plurality of unit angular ranges. For example, as discussedsupra, based the base station may sweep in multiple directions over thetotal region surrounding the base station, using beamforming, and maydetermine a number of UE signals received in each of the multipledirections, where each of the multiple directions corresponds to arespective unit angular region.

In an aspect, the estimation of the number of user equipments in eachunit angular range of the plurality of unit angular ranges based on thenumber of the user equipment signals is based on at least one of: anumber of random access signals received in each unit angular range ofthe plurality of unit angular ranges, a number of scheduling requestsreceived in each unit angular range of the plurality of unit angularranges, a number of beam training requests received in each unit angularrange of the plurality of unit angular ranges, and a number of beamrecovery requests received in each unit angular range of the pluralityof unit angular ranges. For example, as discussed supra, the basestation may determine a number of UEs in a particular region (e.g., aparticular unit angular range) based on a number of scheduling requeststhat the base station has received from the particular region. Forexample, as discussed supra, the base station may determine a number ofUEs in a particular region (e.g., a particular unit angular range) basedon a number of scheduling requests that the base station has receivedfrom the particular region. For example, as discussed supra, the basestation may determine a number of UEs in a particular region (e.g., aparticular unit angular range) based on a number of beam trainingrequests that the base station receives in the particular region. Forexample, as discussed supra, the base station may determine a number ofUEs in a particular region (e.g., a particular unit angular range) basedon a number of beam recovery requests that the base station receives inthe particular region.

At 1506, the base station divides a region surrounding the base stationinto a plurality of sub-regions, where one region of the plurality ofsub-regions covers a greater area than at least one other region of theplurality of sub-regions. For example, as discussed supra, a basestation may divide a coverage area surrounding the base station intosub-regions (e.g., based on a density of UEs in various portions of thecoverage area), such that the base station may transmit the initialaccess signal per sub-region (e.g., for each sub-region, using a beam ina direction corresponding to a respective sub-region). In an aspect, theregion may be an angular region, and the plurality of sub-regions may bea plurality of angular sub-regions. For example, as discussed supra, thearea surrounding the base station may be expressed in an angular range,and each sub-region may cover a respective angular range.

In an aspect, the region surrounding the base station may be dividedinto the plurality of sub-regions based on the received information fromthe network entity. For example, as discussed supra, based on theinformation received from the network entity, the base station maydivide the surrounding region into multiple sub-regions.

In an aspect, the region surrounding the base station may be dividedinto the plurality of sub-regions based on the estimated number of userequipments in each unit angular range of the plurality of unit angularranges. For example, as discussed supra, based on the number of UEsignals received per unit angular region, the base station may determinewhich area is more dense with UEs, such that the base station may dividean area with a higher density of UEs into smaller sub-regions (e.g., subregions with smaller angular coverage). In an aspect, the regionsurrounding the base station may be divided into the plurality ofsub-regions such that a sub-region of the plurality of sub-regions thathas more user equipments per angular area covers a smaller angular areathan a sub-region of the plurality of sub-regions that has less userequipments per angular area. For example, as discussed supra, the basestation may identify a first particular region where more UEs per areaare present or are likely to be present and may divide the firstparticular region into smaller sub-regions (e.g., sub-regions withsmaller angular coverage). For example, as discussed supra, the basestation may identify a second particular region where less UEs per areaare present or are likely to be present and may divide the secondparticular region into one or more larger sub-regions (e.g., sub-regionswith higher angular coverage).

At 1508, the base station assigns each beam of a plurality of beams ofthe base station to a respective sub-region of the plurality ofsub-regions. For example, as discussed supra, the base station mayassign one beam or one set of beams of the base station per sub-region.In an aspect, the base station may assign each beam of a plurality ofbeams of the base station by steering each beam of the plurality beamsto a respective direction correspond to a respective sub-region of theplurality of sub-regions. For example, as discussed supra, whenassigning the beams to sub-regions, the base station may steer each beamsuch that a direction of each beam aligns with a correspondingsub-region.

At 1510, the base station transmits at least one initial access signalin each direction of the plurality of beams using a respective beam ofthe plurality of beams, each direction of the plurality of beamscorresponding to a respective sub-region of the plurality ofsub-regions. For example, as discussed supra, after assigning a beam ora set of beams for each sub-region, the base station may steer beams ofthe base station in directions corresponding to the sub-regions suchthat each beam may be used to transmit the initial access signal in acorresponding sub-region, where each beam may cover approximately thesame number of UEs. In an aspect, the at least one initial access signalmay be transmitted via a millimeter wave transmission. For example, asdiscussed supra, the beams may be beams of mmW communication, and thusthe initial access signal may be transmitted via a mmW transmission. Inan aspect, the at least one initial access signal may include at leastone of a primary synchronization signal, a secondary synchronizationsignal, an extended synchronization signal, a physical broadcastchannel, a beam reference signal, or a downlink broadcast channel. Forexample, as discussed supra, an initial access signal may include atleast one of a PSS, an SSS, an ESS, a PBCH, or a BRS. In an aspect, atleast one initial access signal may be transmitted with the sametransmission rate in each direction of the plurality of beams. Forexample, as discussed supra, for each beam, the same transmission ratemay be used to transmit the initial access signal.

FIG. 16 is a conceptual data flow diagram 1600 illustrating the dataflow between different means/components in an exemplary apparatus 1602.The apparatus may be a base station. The apparatus includes a receptioncomponent 1604, a transmission component 1606, a transmission ratedetermination component 1608, an initial access management component1610, a communication management component 1612, and a region managementcomponent 1614.

According to one aspect of the disclosure, the transmission ratedetermination component 1608 determines a plurality of transmissionrates, each transmission rate for a respective transmission direction ofa plurality of transmission directions. In an aspect, the transmissionrate determination component 1608 may receive, from a network entity1650, via the reception component 1604, information about eachtransmission rate for each transmission direction of the plurality oftransmission directions, and the transmission rate determinationcomponent 1608 may determine each transmission rate based on thereceived information, at 1662 and 1664. In an aspect, the network entityis a centralized controller or a second base station. In an aspect, thesecond base station includes information regarding a number of userequipments aligned in each of the plurality of transmission directions.In an aspect, each transmission direction of the plurality oftransmission directions corresponds with a respective transmission beamof the base station. The transmission rate determination component 1608may forward the transmission rates to the initial access managementcomponent 1610, at 1666.

The initial access management component 1610 transmits, via thecommunication management component 1612 and the transmission component1606, at least one initial access signal in one or more transmissiondirections of the plurality of transmission directions based on thetransmission rate of each transmission direction of the one or moretransmission directions, to UEs such as the UE 1630, at 1668, 1670, and1672. In an aspect, the at least one initial access signal istransmitted via a millimeter wave transmission. In an aspect, the atleast one initial access signal includes at least one of a primarysynchronization signal, a secondary synchronization signal, an extendedsynchronization signal, a physical broadcast channel, or a beamreference signal.

In an aspect, the transmission rate determination component 1608 mayreceive, from UEs such as the UE 1630, via the reception component 1604,at least one of random access signals, scheduling requests, beamtraining requests, or beam recovery requests. In an aspect, thetransmission rate for each transmission direction of the plurality oftransmission directions is determined (e.g., by the transmission ratedetermination component 1608) based on a number of user equipmentsaligned in the transmission direction. In an aspect, the transmissionrate for each transmission direction of the plurality of transmissiondirections is determined (e.g., by the transmission rate determinationcomponent 1608) based on a number of random access signals received inthe transmission direction (e.g., received via the reception component1604 from UE(s) such as the UE 1630, at 1674). In an aspect, thetransmission rate for each transmission direction of the plurality oftransmission directions is determined (e.g., by the transmission ratedetermination component 1608) based on a number of scheduling requestsreceived in the transmission direction (e.g., received via the receptioncomponent 1604 from UE(s) such as the UE 1630, at 1674). In an aspect,the transmission rate for each transmission direction of the pluralityof transmission directions is determined (e.g., by the transmission ratedetermination component 1608) based on at least one of a number of beamtraining requests or a number of beam recovery requests (e.g., receivedvia the reception component 1604 from UE(s) such as the UE 1630, at1674).

The transmission rate determination component 1608 may forward thetransmission rates to the communication management component 1612, at1676. The communication management component 1612 transmits, via thetransmission component 1606, one or more transmission rates of theplurality of transmission rates for the plurality of transmissiondirections, to UE(s) such as the UE 1630, at 1670 and 1672. In anaspect, the one or more transmission rates are transmitted via at leastone of a broadcast transmission or a unicast transmission. In an aspect,the communication management component 1612 transmits the one or moretransmission rates by transmitting, in a first transmission direction ofthe plurality of the transmission directions, a transmission ratecorresponding to the first transmission direction via unicasttransmission, where a UE is located in the first transmission direction.In an aspect, the one or more transmission rates are transmitted via atleast one of a master information block or a system information block.In such an aspect, the master information block is transmitted via aphysical broadcast channel. In such an aspect, the system informationblock is transmitted via at least one of a physical broadcast channel,an extended physical broadcast channel, or RRC communication. Further,in an aspect, the communication management component 1612 maycommunicate to the network entity 1650 via the transmission component1606, at 1670 and 1678.

According to another aspect of the disclosure, the region managementcomponent 1614 divides a region surrounding the base station (e.g.,apparatus 1602) into a plurality of sub-regions, where one region of theplurality of sub-regions covers a greater area than at least one otherregion of the plurality of sub-regions. In an aspect, the region may bean angular region, and the plurality of sub-regions may be a pluralityof angular sub-regions.

In an aspect, the region management component 1614 may receive, from anetwork entity (e.g., the network entity 1650), via the receptioncomponent 1604, information about the plurality of sub-regions, at 1662and 1680. In such an aspect, the region surrounding the base station maybe divided into the plurality of sub-regions based on the receivedinformation from the network entity.

In an aspect, the region management component 1614 may estimate a numberof user equipments in each unit angular range of a plurality of unitangular ranges within the region surrounding the base station, each unitangular range covering a different angular region within the regionsurrounding the base station and having a same angular range size. Insuch an aspect, the region surrounding the base station may be dividedinto the plurality of sub-regions based on the estimated number of userequipments in each unit angular range of the plurality of unit angularranges. In an aspect, at 1404, the region management component 1614 mayreceive, via the reception component 1604, one or more user equipmentsignals in each unit angular range of the plurality of unit angularranges (e.g., from UE 1630, at 1674 and 1680). In an aspect, the numberof user equipments in each unit angular range of the plurality of unitangular ranges may be estimated based on a number of the user equipmentsignals received in each unit angular range of the plurality of unitangular ranges. In such an aspect, the one or more user equipmentsignals may be received in each unit angular range via a beam sweepingthrough the plurality of unit angular ranges. In an aspect, theestimation of the number of user equipments in each unit angular rangeof the plurality of unit angular ranges based on the number of the userequipment signals is based on at least one of: a number of random accesssignals received in each unit angular range of the plurality of unitangular ranges, a number of scheduling requests received in each unitangular range of the plurality of unit angular ranges, a number of beamtraining requests received in each unit angular range of the pluralityof unit angular ranges, and a number of beam recovery requests receivedin each unit angular range of the plurality of unit angular ranges. Inan aspect, the region surrounding the base station is divided into theplurality of sub-regions such that a sub-region of the plurality ofsub-regions that has more user equipments per angular area covers asmaller angular area than a sub-region of the plurality of sub-regionsthat has less user equipments per angular area.

The region management component 1614 assigns each beam of a plurality ofbeams of the base station to a respective sub-region of the plurality ofsub-regions. In an aspect, the base station may assign each beam of aplurality of beams of the base station by steering each beam of theplurality beams to a respective direction correspond to a respectivesub-region of the plurality of sub-regions. The region managementcomponent 1614 may forward information about the plurality ofsub-regions and the assignment of the plurality of beams to the initialaccess management component 1610, at 1682.

The initial access management component 1610 transmits, via thecommunication management component 1612 and the transmission component1606, at least one initial access signal in each direction of theplurality of beams using a respective beam of the plurality of beams, toUEs such as the UE 1630, at 1668, 1670, and 1572, each direction of theplurality of beams corresponding to a respective sub-region of theplurality of sub-regions. In an aspect, the at least one initial accesssignal may be transmitted via a millimeter wave transmission. In anaspect, the at least one initial access signal may include at least oneof a primary synchronization signal, a secondary synchronization signal,an extended synchronization signal, a physical broadcast channel, a beamreference signal, or a downlink broadcast channel. In an aspect, atleast one initial access signal may be transmitted with the sametransmission rate in each direction of the plurality of beams.

The apparatus may include additional components that perform each of theblocks of the algorithm in the aforementioned flowcharts of FIGS. 14 and15. As such, each block in the aforementioned flowcharts of FIGS. 14 and15 may be performed by a component and the apparatus may include one ormore of those components. The components may be one or more hardwarecomponents specifically configured to carry out the statedprocesses/algorithm, implemented by a processor configured to performthe stated processes/algorithm, stored within a computer-readable mediumfor implementation by a processor, or some combination thereof.

FIG. 17 is a diagram 1700 illustrating an example of a hardwareimplementation for an apparatus 1602′ employing a processing system1714. The processing system 1714 may be implemented with a busarchitecture, represented generally by the bus 1724. The bus 1724 mayinclude any number of interconnecting buses and bridges depending on thespecific application of the processing system 1714 and the overalldesign constraints. The bus 1724 links together various circuitsincluding one or more processors and/or hardware components, representedby the processor 1704, the components 1604, 1606, 1608, 1611, 1612,1614, and the computer-readable medium/memory 1706. The bus 1724 mayalso link various other circuits such as timing sources, peripherals,voltage regulators, and power management circuits, which are well knownin the art, and therefore, will not be described any further.

The processing system 1714 may be coupled to a transceiver 1710. Thetransceiver 1710 is coupled to one or more antennas 1720. Thetransceiver 1710 provides a means for communicating with various otherapparatus over a transmission medium. The transceiver 1710 receives asignal from the one or more antennas 1720, extracts information from thereceived signal, and provides the extracted information to theprocessing system 1714, specifically the reception component 1604. Inaddition, the transceiver 1710 receives information from the processingsystem 1714, specifically the transmission component 1606, and based onthe received information, generates a signal to be applied to the one ormore antennas 1720. The processing system 1714 includes a processor 1704coupled to a computer-readable medium/memory 1706. The processor 1704 isresponsible for general processing, including the execution of softwarestored on the computer-readable medium/memory 1706. The software, whenexecuted by the processor 1704, causes the processing system 1714 toperform the various functions described supra for any particularapparatus. The computer-readable medium/memory 1706 may also be used forstoring data that is manipulated by the processor 1704 when executingsoftware. The processing system 1714 further includes at least one ofthe components 1604, 1606, 1608, 1611, 1612, 1614. The components may besoftware components running in the processor 1704, resident/stored inthe computer readable medium/memory 1706, one or more hardwarecomponents coupled to the processor 1704, or some combination thereof.The processing system 1714 may be a component of the eNB 310 and mayinclude the memory 376 and/or at least one of the TX processor 316, theRX processor 370, and the controller/processor 375.

In one configuration, the apparatus 1602/1602′ for wirelesscommunication includes means for determining a plurality of transmissionrates, each transmission rate for a respective transmission direction ofa plurality of transmission directions, and means for transmitting atleast one initial access signal in one or more transmission directionsof the plurality of transmission directions based on the transmissionrate of each transmission direction of the one or more transmissiondirections. In an aspect, the apparatus 1602/1602′ may further includemeans for transmitting one or more transmission rates of the pluralityof transmission rates for the plurality of transmission directions. Inan aspect, the means for transmitting the one or more transmission ratesis configured to transmit, in a first transmission direction of theplurality of the transmission directions, a transmission ratecorresponding to the first transmission direction via unicasttransmission, where a UE is located in the first transmission direction.In an aspect, the apparatus 1602/1602′ may further include means forreceiving, from a network entity, information about each transmissionrate for each transmission direction of the plurality of transmissiondirections, where each transmission rate is determined based on thereceived information.

In another configuration, the apparatus 1602/1602′ for wirelesscommunication includes means for dividing a region surrounding the basestation into a plurality of sub-regions, where one region of theplurality of sub-regions covers a greater area than at least one otherregion of the plurality of sub-regions, means for assigning each beam ofa plurality of beams of the base station to a respective sub-region ofthe plurality of sub-regions, and means for transmitting at least oneinitial access signal in each direction of the plurality of beams usinga respective beam of the plurality of beams, each direction of theplurality of beams corresponding to a respective sub-region of theplurality of sub-regions. In an aspect, the apparatus 1602/1602′ mayinclude means for receiving one or more user equipment signals in eachunit angular range of the plurality of unit angular ranges, where thenumber of user equipments in each unit angular range of the plurality ofunit angular ranges is estimated based on a number of the user equipmentsignals received in each unit angular range of the plurality of unitangular ranges. In an aspect, the means for assigning each beam of theplurality of beams is configured to steer each beam of the pluralitybeams to a respective direction correspond to a respective sub-region ofthe plurality of sub-regions. In an aspect, the apparatus 1602/1602′ mayinclude means for receiving, from a network entity, information aboutthe plurality of sub-regions, where the region surrounding the basestation may be divided into the plurality of sub-regions based on thereceived information.

The aforementioned means may be one or more of the aforementionedcomponents of the apparatus 1602 and/or the processing system 1714 ofthe apparatus 1602′ configured to perform the functions recited by theaforementioned means. As described supra, the processing system 1714 mayinclude the TX Processor 316, the RX Processor 370, and thecontroller/processor 375. As such, in one configuration, theaforementioned means may be the TX Processor 316, the RX Processor 370,and the controller/processor 375 configured to perform the functionsrecited by the aforementioned means.

FIG. 18 is a flowchart 1800 of a method of wireless communication. Themethod may be performed by a UE (e.g., the UE 104, 722, 822, 902, theapparatus 1902/1902′). At 1802, the UE receives, from a base station,one or more transmission rates of the base station for a plurality oftransmission directions, where each transmission rate is determined fora respective transmission direction of the plurality of transmissiondirections. For example, as discussed supra, the base station maytransmit the base station's transmission rates for differenttransmission directions to one or more UEs. In an aspect, the one ormore transmission rates may be received via a millimeter wavetransmission. In an aspect, the one or more transmission rates may bereceived via at least one of a broadcast transmission or a unicasttransmission. For example, as discussed supra, in one approach, the basestation may transmit all of the base station's transmission rates fordifferent transmission directions by broadcasting the base station'stransmission rates. For example, as discussed supra, in anotherapproach, the base station may transmit all of the base station'stransmission rates for different transmission directions to a UE via aunicast transmission. At 1804, the UE determines a first transmissionrate of the base station corresponding to a first transmission directionof the plurality of transmission directions, where the UE is located inthe first transmission direction. In an aspect, the UE may receive theone or more transmission rates by receiving, in the first transmissiondirection, the first transmission rate from the base station. Forexample, as discussed supra, when the UE receives base station'stransmission rate(s), the UE may determine the base station'stransmission rate(s) for a particular transmission direction that isaligned with the UE. For example, as discussed supra, the base stationmay convey to the UE information about the particular direction alignedwith the UE and a transmission rate for the particular direction.

At 1806, the UE configures at least one communication setting forcommunicating with the base station based on the first transmission rateof the base station. For example, as discussed supra, based on the basestation's transmission rate(s), a UE may configure certain communicationsettings for communicating with the base station. In an aspect, the atleast one communication setting may include an activation time of the UEto activate a connection of the UE with the base station. In such anaspect, the UE may activate the connection with the base station inresponse to receiving paging information from the base station. In suchan aspect, the activation time of the UE may become more frequent as thefirst transmission rate of the base station increases. For example, asdiscussed supra, the UE may configure an activation time to indicate howoften to wake up to activate a connection of the UE with the basestation, based on a transmission rate of the base station for aparticular transmission direction aligned with the UE. For example, asdiscussed supra, the UE may determine to wake up more often if thetransmission rate of the base station is higher for the particulartransmission direction where the UE is aligned.

In an aspect, the one or more transmission rates may be received via atleast one of a master information block or a system information block.In such an aspect, the master information block may be received via aphysical broadcast channel. In such an aspect, the system informationblock may be received via at least one of a physical broadcast channel,an extended physical broadcast channel, or radio resource control (RRC)communication. For example, as discussed supra, the base station maytransmit (to the UE) the information about transmission rates fordifferent transmission directions via a MIB and/or a SIB. For example,as discussed supra, the MIB may be transmitted via a PBCH. For example,as discussed supra, the SIB may be transmitted via at least one of aPBCH, an extended PBCH, or RRC signaling.

FIG. 19 is a conceptual data flow diagram 1900 illustrating the dataflow between different means/components in an exemplary apparatus 1902.The apparatus may be a UE. The apparatus includes a reception component1904, a transmission component 1906, a transmission rate managementcomponent 1908, and a communication management component 1910.

The transmission rate management component 1908 receives via thereception component 1904, from a base station (e.g., base station 1950),one or more transmission rates of the base station for a plurality oftransmission directions, at 1962 and 1964, where each transmission rateis determined for a respective transmission direction of the pluralityof transmission directions. In an aspect, the one or more transmissionrates are received via a millimeter wave transmission. In an aspect, theone or more transmission rates are received via at least one of abroadcast transmission or a unicast transmission. The transmission ratemanagement component 1908 determines a first transmission rate of thebase station corresponding to a first transmission direction of theplurality of transmission directions, where the UE is located in thefirst transmission direction. In an aspect, the transmission ratemanagement component 1908 may receive the one or more transmission ratesby receiving, in the first transmission direction, the firsttransmission rate from the base station. The transmission ratemanagement component 1908 may forward the first transmission rate of thebase station to the communication management component 1910, at 1966.

The communication management component 1910 configures (e.g., via thetransmission component 1906, at 1968) at least one communication settingfor communicating with the base station based on the first transmissionrate of the base station. The communication management component 1910may communicate to the base station 1950 via the transmission component1906, at 1970, based on the communication setting. In an aspect, the atleast one communication setting comprises an activation time of the UEto activate a connection of the UE with the base station. In such anaspect, the UE activates the connection with the base station inresponse to receiving paging information from the base station. In suchan aspect, the activation time of the UE becomes more frequent as thefirst transmission rate of the base station increases

In an aspect, the one or more transmission rates are received via atleast one of a master information block or a system information block.In such an aspect, the master information block is received via aphysical broadcast channel. In such an aspect, the system informationblock is received via at least one of a physical broadcast channel, anextended physical broadcast channel, or RRC communication.

The apparatus may include additional components that perform each of theblocks of the algorithm in the aforementioned flowcharts of FIG. 18. Assuch, each block in the aforementioned flowcharts of FIG. 18 may beperformed by a component and the apparatus may include one or more ofthose components. The components may be one or more hardware componentsspecifically configured to carry out the stated processes/algorithm,implemented by a processor configured to perform the statedprocesses/algorithm, stored within a computer-readable medium forimplementation by a processor, or some combination thereof.

FIG. 20 is a diagram 2000 illustrating an example of a hardwareimplementation for an apparatus 1902′ employing a processing system2014. The processing system 2014 may be implemented with a busarchitecture, represented generally by the bus 2024. The bus 2024 mayinclude any number of interconnecting buses and bridges depending on thespecific application of the processing system 2014 and the overalldesign constraints. The bus 2024 links together various circuitsincluding one or more processors and/or hardware components, representedby the processor 2004, the components 1904, 1906, 1908, 1910, and thecomputer-readable medium/memory 2006. The bus 2024 may also link variousother circuits such as timing sources, peripherals, voltage regulators,and power management circuits, which are well known in the art, andtherefore, will not be described any further.

The processing system 2014 may be coupled to a transceiver 2010. Thetransceiver 2010 is coupled to one or more antennas 2020. Thetransceiver 2010 provides a means for communicating with various otherapparatus over a transmission medium. The transceiver 2010 receives asignal from the one or more antennas 2020, extracts information from thereceived signal, and provides the extracted information to theprocessing system 2014, specifically the reception component 1904. Inaddition, the transceiver 2010 receives information from the processingsystem 2014, specifically the transmission component 1906, and based onthe received information, generates a signal to be applied to the one ormore antennas 2020. The processing system 2014 includes a processor 2004coupled to a computer-readable medium/memory 2006. The processor 2004 isresponsible for general processing, including the execution of softwarestored on the computer-readable medium/memory 2006. The software, whenexecuted by the processor 2004, causes the processing system 2014 toperform the various functions described supra for any particularapparatus. The computer-readable medium/memory 2006 may also be used forstoring data that is manipulated by the processor 2004 when executingsoftware. The processing system 2014 further includes at least one ofthe components 1904, 1906, 1908, 1910. The components may be softwarecomponents running in the processor 2004, resident/stored in thecomputer readable medium/memory 2006, one or more hardware componentscoupled to the processor 2004, or some combination thereof. Theprocessing system 2014 may be a component of the UE 350 and may includethe memory 360 and/or at least one of the TX processor 368, the RXprocessor 356, and the controller/processor 359.

In one configuration, the apparatus 1902/1902′ for wirelesscommunication includes means for receiving, from a base station, one ormore transmission rates of the base station for a plurality oftransmission directions, where each transmission rate is determined fora respective transmission direction of the plurality of transmissiondirections, means for determining a first transmission rate of the basestation corresponding to a first transmission direction of the pluralityof transmission directions, where the UE is located in the firsttransmission direction, and means for configuring at least onecommunication setting for communicating with the base station based onthe first transmission rate of the base station. In an aspect, the meansfor receiving the one or more transmission rates is configured toreceive, in the first transmission direction, the first transmissionrate from the base station.

The aforementioned means may be one or more of the aforementionedcomponents of the apparatus 1902 and/or the processing system 2014 ofthe apparatus 1902′ configured to perform the functions recited by theaforementioned means. As described supra, the processing system 2014 mayinclude the TX Processor 368, the RX Processor 356, and thecontroller/processor 359. As such, in one configuration, theaforementioned means may be the TX Processor 368, the RX Processor 356,and the controller/processor 359 configured to perform the functionsrecited by the aforementioned means.

It is understood that the specific order or hierarchy of blocks in theprocesses/flowcharts disclosed is an illustration of exemplaryapproaches. Based upon design preferences, it is understood that thespecific order or hierarchy of blocks in the processes/flowcharts may berearranged. Further, some blocks may be combined or omitted. Theaccompanying method claims present elements of the various blocks in asample order, and are not meant to be limited to the specific order orhierarchy presented.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” The word “exemplary” is used hereinto mean “serving as an example, instance, or illustration.” Any aspectdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other aspects. Unless specifically statedotherwise, the term “some” refers to one or more. Combinations such as“at least one of A, B, or C,” “one or more of A, B, or C,” “at least oneof A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or anycombination thereof” include any combination of A, B, and/or C, and mayinclude multiples of A, multiples of B, or multiples of C. Specifically,combinations such as “at least one of A, B, or C,” “one or more of A, B,or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and“A, B, C, or any combination thereof” may be A only, B only, C only, Aand B, A and C, B and C, or A and B and C, where any such combinationsmay contain one or more member or members of A, B, or C. All structuraland functional equivalents to the elements of the various aspectsdescribed throughout this disclosure that are known or later come to beknown to those of ordinary skill in the art are expressly incorporatedherein by reference and are intended to be encompassed by the claims.Moreover, nothing disclosed herein is intended to be dedicated to thepublic regardless of whether such disclosure is explicitly recited inthe claims. The words “module,” “mechanism,” “element,” “device,” andthe like may not be a substitute for the word “means.” As such, no claimelement is to be construed as a means plus function unless the elementis expressly recited using the phrase “means for.”

What is claimed is:
 1. A method of wireless communication by a basestation, comprising: determining a plurality of transmission rates, eachtransmission rate for a respective transmission direction of a pluralityof transmission directions; and transmitting at least one access signalin one or more transmission directions of the plurality of transmissiondirections based on the transmission rate of each transmission directionof the one or more transmission directions, wherein the at least oneaccess signal is transmitted via a millimeter wave transmission; whereineach transmission direction of the plurality of transmission directionscorresponds with a respective transmission beam of the base station. 2.The method of claim 1, wherein the at least one access signal includesat least one of a primary synchronization signal, a secondarysynchronization signal, an extended synchronization signal, a physicalbroadcast channel, or a beam reference signal.
 3. The method of claim 1,wherein the transmission rate for each transmission direction of theplurality of transmission directions is determined based on at least oneof: a number of user equipments aligned in the transmission direction, anumber of random access signals received in the transmission direction,a number of scheduling requests received in the transmission direction,or at least one of a number of beam training requests or a number ofbeam recovery requests.
 4. The method of claim 1, further comprising:transmitting one or more transmission rates of the plurality oftransmission rates for the plurality of transmission directions.
 5. Themethod of claim 4, wherein the transmitting the one or more transmissionrates comprises: transmitting, in a first transmission direction of theplurality of transmission directions, a transmission rate correspondingto the first transmission direction via unicast transmission, wherein aUE is located in the first transmission direction.
 6. The method ofclaim 4, wherein the one or more transmission rates are transmitted viaat least one of a master information block or a system informationblock.
 7. The method of claim 1, further comprising: receiving, from anetwork entity, information about each transmission rate for eachtransmission direction of the plurality of transmission directions,wherein each transmission rate is determined based on the receivedinformation.
 8. A method of wireless communication by a user equipment(UE), comprising: receiving, from a base station, one or moretransmission rates of the base station for a plurality of transmissiondirections, wherein each transmission rate is determined for arespective transmission direction of the plurality of transmissiondirections, wherein each transmission direction of the plurality oftransmission directions corresponds with a respective transmission beam,wherein the one or more transmission rates are received via a millimeterwave transmission; determining a first transmission rate of the basestation corresponding to a first transmission direction of the pluralityof transmission directions, wherein the UE is located in the firsttransmission direction; and configuring at least one communicationsetting for communicating with the base station based on the firsttransmission rate of the base station.
 9. The method of claim 8, whereinthe at least one communication setting comprises an activation time ofthe UE to activate a connection of the UE with the base station.
 10. Themethod of claim 9, wherein the activation time of the UE becomes morefrequent as the first transmission rate of the base station increases.11. The method of claim 8, wherein the receiving the one or moretransmission rates comprises: receiving, in the first transmissiondirection, the first transmission rate from the base station.
 12. Themethod of claim 8, wherein the one or more transmission rates arereceived via at least one of a master information block or a systeminformation block.
 13. A base station for wireless communication,comprising: a memory; and at least one processor coupled to the memoryand configured to: determine a plurality of transmission rates, eachtransmission rate for a respective transmission direction of a pluralityof transmission directions; and transmit at least one access signal inone or more transmission directions of the plurality of transmissiondirections based on the transmission rate of each transmission directionof the one or more transmission directions, wherein the at least oneaccess signal is transmitted via a millimeter wave transmission; whereineach transmission direction of the plurality of transmission directionscorresponds with a respective transmission beam of the base station. 14.The base station of claim 13, wherein the at least one access signalincludes at least one of a primary synchronization signal, a secondarysynchronization signal, an extended synchronization signal, a physicalbroadcast channel, or a beam reference signal.
 15. The base station ofclaim 13, wherein the transmission rate for each transmission directionof the plurality of transmission directions is determined based on atleast one of: a number of user equipments aligned in the transmissiondirection, a number of random access signals received in thetransmission direction, a number of scheduling requests received in thetransmission direction, or at least one of a number of beam trainingrequests or a number of beam recovery requests.
 16. The base station ofclaim 13, wherein the at least one processor is further configured to:transmit one or more transmission rates of the plurality of transmissionrates for the plurality of transmission directions.
 17. The base stationof claim 16, wherein the at least one processor configured to transmitthe one or more transmission rates is configured to: transmit, in afirst transmission direction of the plurality of the transmissiondirections, a transmission rate corresponding to the first transmissiondirection via unicast transmission, wherein a UE is located in the firsttransmission direction.
 18. The base station of claim 16, wherein theone or more transmission rates are transmitted via at least one of amaster information block or a system information block.
 19. The basestation of claim 13, wherein the at least one processor is furtherconfigured to: receive, from a network entity, information about eachtransmission rate for each transmission direction of the plurality oftransmission directions, wherein each transmission rate is determinedbased on the received information.
 20. A user equipment (UE) forwireless communication, comprising: a memory; and at least one processorcoupled to the memory and configured to: receive, from a base station,one or more transmission rates of the base station for a plurality oftransmission directions, wherein each transmission rate is determinedfor a respective transmission direction of the plurality of transmissiondirections, wherein each transmission direction of the plurality oftransmission directions corresponds with a respective transmission beamof the base station, wherein the one or more transmission rates arereceived via a millimeter wave transmission; determine a firsttransmission rate of the base station corresponding to a firsttransmission direction of the plurality of transmission directions,wherein the UE is located in the first transmission direction; andconfigure at least one communication setting for communicating with thebase station based on the first transmission rate of the base station.21. The UE of claim 20, wherein the at least one communication settingcomprises an activation time of the UE to activate a connection of theUE with the base station.
 22. The UE of claim 21, wherein the activationtime of the UE becomes more frequent as the first transmission rate ofthe base station increases.
 23. The UE of claim 20, wherein the at leastone processor configured to receive the one or more transmission ratesis configured to: receive, in the first transmission direction, thefirst transmission rate from the base station.
 24. The UE of claim 20,wherein the one or more transmission rates are received via at least oneof a master information block or a system information block.